Mathematics X
Mathematics X
Mathematics X
KENDRIYA VIDYALAYA
SANGATHAN JAIPUR REGION
Sh. B. L. MORODIA
Deputy
Commissioner
KVS JAIPUR
REGION
The prime factorisation of a natural number is unique, except for the order of its factors.
Property of HCF and LCM of two positive integers ‘a’ and ‘b’:
HCF (a, b) = Product of the smallest power of each common prime factor in the numbers.
LCM (a, b) = Product of the greatest power of each prime factor, involved in the numbers.
PRACTICE QUESTIONS:
1. Complete the missing entries in the following factor tree:
(a) 42 and 21
(b) 24 and 12
(c) 7 and 3
(d) 84 and 42
2 The H.C.F. and the L.C.M. of 12, 21, 15 respectively are:
(a) 3, 140 (b) 12, 420 (c) 3, 420 (d) 420, 3
3 The H.C.F. of smallest prime number and the smallest composite number is .......... .
(a) 1 (b) 2 (c) 4 (d) none of these
Answer Key
Q. No. Answers Q. No. Answers
1 a 14 (a) Both assertion (A) and reason (R) are true and reason
(R) is the correct explanation of assertion (A).
2 c 15 (c) Assertion (A) is true but reason (R) is false.
3 b 16 2:1
4 a 17 m=8
5 a 18 At 10 AM
8 composite number 19. (i) 9 rooms (ii) 7 rooms
(iii) 21 rooms OR 22 rooms
9 8n cannot be end with digit zero 20. (i) 48 (ii) 14
(iii) 7 OR 72 kg
10 HCF (26,169) = 13 21. a is odd, b is odd, a+b is even. Smallest prime factor of
a+b =2
11 HCF=6 LCM=360 22. 𝑥 2 − 4 = ( 𝑥 + 2)(𝑥 − 2) 𝑎𝑛𝑑
𝑥 4 − 16 = (𝑥 2 + 4)( 𝑥 + 2)(𝑥 − 2)
LCM = (𝑥 2 + 4)( 𝑥 + 2)(𝑥 − 2) = 𝑥 4 − 16
12 x=4,y=3 and n=5 23. 𝑥 3 − 3𝑥 + 2 = (𝑥 − 1) ( 𝑥 − 1)(𝑥 + 2)𝑎𝑛𝑑
𝑥 2 − 4𝑥 + 3 = (𝑥 − 1)(𝑥 − 3).
HCF = (x – 1)
13 (b) Both assertion (A) and reason 24. HCF = p and LCM = q
(R) are true but reason (R) is not
the correct explanation of assertion
(A).
25. No
CHAPTER - 2
POLYNOMIALS
An expression of the form p(x) = a 0 + a1x + a 2 x 2 + ••• ........... +anxn where a n ≠ 0 is called a polynomial in one variable x of degree
n, where; a 0 , .................................................................................................. an, are constants and they are called the coefficients of x 0 , x, x 2
.............................................................................................................................. x n . Each power of x is a non-negative integer.
Eg: - 5x 2 - 5x + 1 is a polynomial of degree 2.
Note: √𝒙 + 3 is not a polynomial
• A polynomial p(x) = ax + b of degree 1 is called a linear polynomial Eg: 5x - 3,2x etc.
• A polynomial p(x) = ax 2 + bx + c of degree 2 is called a quadratic polynomial
Eg: 5x 2 + x - 1
• A polynomial p(x) = ax 3 + bx 2 + cx + d of degree 3 is called a cubic polynomial.
Eg: √3x3 - x + 4, x 3 - 1 etc.
Zeroes of a polynomial: A real number k is called a zero of polynomial p(x) if p(k)=0. If the graph of y= p(x)
intersects the X-axis n times, the number of zeroes of y= p(x) is n. If the graph of x= p(y) intersects the Y-axis n
times, the number of zeroes of x= p(y) is n.
• A linear polynomial has only one zero.
• A quadratic polynomial has at most two zeroes.
• A cubic polynomial has at most three zeroes.
• A polynomial of degree n has at most n zeroes.
Relationship between zeroes and coefficients of a quadratic polynomial:
𝑓𝑜𝑟 𝑞𝑢𝑎𝑑𝑟𝑎𝑡𝑖𝑐 𝑝𝑜𝑙𝑦𝑛𝑜𝑚𝑖𝑎𝑙 ∶ 𝑖𝑓 𝛼 & 𝛽 𝑎𝑟𝑒 𝑧𝑒𝑟𝑜𝑒𝑠 𝑜𝑓𝑎 𝑞𝑢𝑎𝑑𝑟𝑎𝑡𝑖𝑐 𝑝𝑜𝑙𝑦𝑛𝑜𝑚𝑖𝑎𝑙 𝑎𝑥 2 + 𝑏𝑥 + 𝑐 then
𝑏 − (𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑜𝑓 𝑥 )
1. 𝑆𝑢𝑚 𝑜𝑓 𝑧𝑒𝑟𝑜𝑒𝑠 = 𝛼 + 𝛽 = − =
𝑎 (𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑜𝑓 𝑥 2 )
𝑐 (𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡 𝑡𝑒𝑟𝑚)
2. 𝑃𝑟𝑜𝑑𝑢𝑐𝑡 𝑜𝑓 𝑧𝑒𝑟𝑜𝑒𝑠 = 𝛼𝛽 = =
𝑎 (𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝑜𝑓 𝑥 2 )
A quadratic polynomial whose zeroes are 𝛼 and 𝛽 is given by: 𝑥 2 − (𝛼 + 𝛽 )𝑥 + 𝛼𝛽= x2 – Sx +P.
3. If a and b are the zeroes of a polynomial such that a + b = - 6 and ab = - 4, then write the polynomial.
(a) x2 - 6x - 4 = 0 (b) x2 + 6x - 4 = 0 (c) x2 + 6x + 4 = 0 (d) x2 - 6x + 4 = 0
4. The zeroes of the polynomial x 2 - 3x - m(m + 3) are:
(a) m, m + 3 (b) - m, m + 3 (c) m, - (m + 3) (d) - m, - (m + 3)
5. The zeroes of the quadratic polynomial x + 99x + 127 are:
2
1. From the above graph, how many numbers of zeroes are there?
2. Find the zeroes of the polynomial.
3. Find the sum and product of the zeroes of the quadratic polynomial: px 2+qx+pq.
OR
1
Write a polynomial whose sum of zeroes and product of zeroes are √2 and 3.
29. The Gateway of India is an arch-monument built in the early 20th century in the city of Mumbai (Bombay),
India. It was erected to commemorate the landing of King-Emperor George V, the first British monarch to
visit India, in December 1911 at Strand Road near Wellington Fountain.
1. If the slope of the gateway is represented by quadratic polynomial x2 -2x -8, then find its zeroes.
2. Find the quadratic equation for parabolic curve whose sum of zeroes is 6 and product of zeroes is 0
respectively.
3. Find the number of real zeroes of the polynomial f(x)= (x-2)2 + 4.
OR
1 1
Write a quadratic polynomial whose zeroes are 2 and 2.
ANSWER KEY
Q1. D Q2. C Q3. B Q4. B Q5. B Q6. A Q7. D Q8. B
Q9. A Q10. A Q11. A Q12. A Q13. A Q14. D Q15 C
1
Q16. 𝑍𝑒𝑟𝑜𝑒𝑠 𝑜𝑓 𝑡ℎ𝑒 𝑝𝑜𝑙𝑦𝑛𝑜𝑚𝑖𝑎𝑙 𝑎𝑟𝑒 𝛼 𝑎𝑛𝑑 𝛼 , 𝛼 × 𝛼 =
1
Q17. 𝑠𝑢𝑚 𝑜𝑓 𝑡ℎ𝑒 𝑝𝑜𝑙𝑦𝑛𝑜𝑚𝑖𝑎𝑙𝑠 =
𝑏 𝑐 1 1
4𝑎
, 𝑎2 + 4 = 4𝑎 , 𝑎 = 2 − 𝑎 , 𝑝𝑟𝑜𝑑𝑢𝑐𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑝𝑜𝑙𝑦𝑛𝑜𝑚𝑖𝑎𝑙𝑠 = 𝑎 , 𝛼 + 𝛽 − 2𝛼𝛽 =
𝑎 2 +4
{(𝛼+𝛽)−2(𝛼𝛽)2 } 𝑏 2𝑐
= − (𝑐 + )
𝛼𝛽 𝑎
Q18. 𝛼 + 𝛽 = −𝑝 , 𝛼𝛽 = 45 −𝑏±√𝑏2 −4𝑎𝑐
Q19. 𝑞𝑢𝑎𝑑𝑟𝑎𝑡𝑖𝑐 𝑓𝑜𝑟𝑚𝑢𝑙𝑎 =
⟹ 𝑔𝑖𝑣𝑒𝑛, (𝛼 − 𝛽 )2 = 144 2𝑎
(𝛼 + 𝛽 )2 − 4𝛼𝛽 = 144 𝛼 = −3 + √7 𝑎𝑛𝑑 𝛽 = −3 − √7
⟹ (−𝑝)2 − 4 × 45 = 144 1 1 1 1
∴ 𝛼 −1 + 𝛽 −1 = + ⟹ + ⟹ −3
⟹ 𝑝 = ±18 𝛼 𝛽 (−3 + √7) −3 − √7
𝛼 3
Q20. = ⟹ 𝛼 = 𝛽
3
Q21. 𝛼 + 𝛽 = 𝛼𝛽
𝛽 2 2 𝑏 𝑐
𝑐 3 ⟹ − =
⟹ 𝛼𝛽 = = 6 ⟹ 𝛽 2 = 6 ⟹ 𝛽 = ±2 𝑎𝑛𝑑 𝛼 = ±3 𝑎 𝑎
𝑎 2 2 3𝑘
𝑏 −𝑘 ⟹ − =
∴ 𝛼+𝛽 = − = − = 𝑘 ⟹ ±2 ± 3 = 𝑘 ⟹ 𝑘 𝑘 𝑘
𝑎 1 2
= ±5 ⟹ 𝑘= −
3
7 3 7 2 𝑏
Q23. 𝛼 + 𝛽 = − 𝑎 = 4√3 𝑎𝑛𝑑 𝛼𝛽 = 3 ⟹ 𝛼 + 𝛽 − 𝛼𝛽 =
Q22. 𝑝 + 𝑞 = 2 ⟹ 𝑝𝑞 = 2 ⟹ (𝑝 + 𝑞 )2 = (2)
37 4√3 − 3 ⟹ √3(4 − √3)
⟹ 𝑝2 + 𝑞 2 =
4
Q24. 4𝑢2 + 8 Q25. 𝑦 2 + 5𝑦 + 𝑚
⟹ 𝑏𝑦 𝑞𝑢𝑎𝑑𝑟𝑎𝑡𝑖𝑐 𝑓𝑜𝑟𝑚𝑢𝑙𝑎 − 1 ± 1 ⟹ 𝑎 + 𝑝 = −5 ⟹ 𝑎𝑝 = 𝑚
⟹ 𝑒𝑖𝑡ℎ𝑒𝑟 − 1 + 1 = 0 𝑜𝑟 − 1 − 1 = −2 ⟹ (𝑎 + 𝑝)2 − 𝑎𝑝 = 24
𝑏 8 ⟹ (−5)2 − 𝑚 = 24
⟹ 𝑎𝑠 𝑤𝑒 𝑘𝑛𝑜𝑤 𝑡ℎ𝑎𝑡 𝛼 + 𝛽 = − ⟹ 0 + (−2) = −
𝑎 4 ⟹ 25 − 𝑚 = 24
𝑐 ⟹𝑚=1
⟹ −2 = −2 𝑎𝑛𝑑 𝛼𝛽 = ⟹ 0 × (−2)
𝑎
0
= ⟹ 0 = 0 𝐻. 𝑃.
4
Q26. 𝑥 2 − 𝑥 − 2 Q27. (1) 40
⟹ 𝑎 + 𝑝 = 1 𝑎𝑛𝑑 𝑎𝑝 = 2 (2) 20
⟹ 𝑜𝑡ℎ𝑒𝑟 𝑧𝑒𝑟𝑜𝑒𝑠 𝑎𝑟𝑒 2𝑎 + 1 𝑎𝑛𝑑 2𝑝 + 1 (3) 𝑥 2 − 59𝑥 + 814
⟹ 𝛼 + 𝛽 = 2𝑎 + 1 + 2𝑝 + 1 ⟹ 2(𝑎 + 𝑝 + 1) OR
⟹ 2(1 + 1) ⟹ 4 (3) Yes, 2/3 is a zero of the given polynomial.
𝛼𝛽 = (2𝑎 + 1)(2𝑝 + 1)
⟹ 2(𝑎 + 𝑝) + 4𝑎𝑝 + 1 ⟹ 2 × 1 + 4 × (−2) + 1 = −5
∴ 𝑁𝑒𝑤 𝑝𝑜𝑙𝑦𝑛𝑜𝑚𝑖𝑎𝑙 = 𝑥 2 − (𝛼 + 𝛽 )𝑥 + 𝛼𝛽
⟹ 𝑥 2 − 4𝑥 − 5
Q28. (1) 3 Q29. (1) By the middle term splitting or quadratic formula
(2) -2,0,2 𝑥 = 4, −2
𝑞
(3) Sum of zeroes = − 𝑝 and product of zeroes = q (2) 𝑥 2 − (𝛼 + 𝛽 )𝑥 + 𝛼𝛽
= 𝑥 2 − 6𝑥 + 0
OR
1 = 𝑥 2 − 6𝑥
(3) = 𝑥 2 − √2𝑥 + 3 (3) Number of real zeroes = 0, because D< 0
= 3𝑥 2 − 3√2𝑥 + 1 OR
(3) 𝑥 2 − (𝛼 + 𝛽 )𝑥 + 𝛼𝛽
1
= 𝑥2 − 𝑥 + 4
= 4𝑥 2 − 4𝑥 + 1
CHAPTER 3
PAIR OF LINEAR EQUATIONS IN TWO VARIABLES
ALGEBRAIC INTERPRETATION OF PAIR OF LINEARE QUATIONS IN TWO VARIABLES
The pair of linear equations represented by these lines a1x+b1y+c1=0 and a2x +b2y +c2 = 0
a1x + b1y + c1 = 0 𝑎1
=
𝑏1
= 𝑐1
𝑐 Coincident lines Infinitely many
𝑎2 𝑏2
2 a2x + b2y + c2 = 0
2 solutions
(consistent)
a1x + b1y + c1 = 0 𝑎1
=
𝑏1
≠
𝑐1 Parallel lines No solution
𝑎2 𝑏2 𝑐2
The value of k for which the system of linear equations x + 2y = 3, 5x + ky + 7 = 0 is inconsistent is equal to:
4 (a) 3 (b) – 4 (c) 4 (d) 10
The values of x and y in 2x + 3y = 2 and x - 2y = 8 are:
5
(a) - 4, 2 (b) - 4, - 2 (c) 4, - 2 (d) 4, 2
Sum of two numbers is 35 and their difference is 13, then the numbers are:
6 (a) 24 and 12 (b) 24 and 11 (c) 12 and 11 (d) none of these
x and y are two different digits. If the sum of the original number and the number formed by reversing the digits
7 is a perfect square, then value of x + y is
(a) 10 (b) 11 (c) 12 (d) 13
One equation of a pair of dependent linear equations −5x + 7y = 2. The second equation can be
8 (a) 10x + 14y + 4 = 0 (b) -10x -14y - 4 = 0
(c) -10x + 14y + 4 = 0 (d) 10x – 14y = - 4
9 If x = a and y = b is the solution of the equations x – y = 2 and x + y = 4, then the values of a2 and b2 are,
respectively
(a) 9 and 4 (b) 1and 4 (c) 9 and 1 (d) 4 and 25
10 The pair of equations x = b and y = a graphically represents lines which are
(a) parallel (b) intersecting at (b, a)
(c) coincident (d) intersecting at (a, b)
DIRECTION : In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice
as:
(a)Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b)Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c)Assertion (A) is true but reason (R) is false.
(d)Assertion (A) is false but reason (R) is true.
Q.1 Assertion : The linear equations x – 2y – 3 = 0 and 3x + 4y – 20 = 0 have exactly one solution.
Reason : If the pair of lines are parallel, then the pair has no solution and is called inconsistent pair of equations.
Q.2 Assertion : The graph of the linear equations 3x + 2y = 12 and 5x – 2y = 4 gives a pair of intersecting lines.
a b1
Reason : The graph of linear equations a1x+b1y+c1=0 and a2x +b2y +c2 = 0 gives a pair of intersecting lines if a1 ≠
2 b2
Q.3 Assertion : A pair of linear equations has no solution (s) if it is represented by intersecting lines graphically.
Reason: If the pair of lines are intersecting, then the pair has unique solution and is called consistent pair of equations.
Q1 MASK: Masks are an additional step to help prevent people from getting and spreading COVID-19. They
provide a barrier that keeps respiratory droplets from spreading. Wear a mask and take every day preventive
actions in public settings.
Due to ongoing Corona virus outbreak, Wellness Medical store has started selling masks of decent quality. The
store is selling two types of masks currently type A and type B. The cost of type A mask is Rs.15 and of type B
mask is Rs.20. In the month of April, 2020, the store sold 100 masks for total sales of Rs.1650
(i) How many masks of type A were sold in the month of April?
(ii) How many masks of type B were sold in the month of April?
(iii) If the store had sold 50 masks of each type, what would be its sale in the month of April?
OR
If the cost of type A mask would have been Rs.20 and of type B mask be Rs.25, then find the total sale for the
month of April.
Q2 At some point, it’s time to gently ease, kids off the parental gravy train. The circle graph shows the percentage
of parents who think significant financial support should end at various milestones
The difference in the percentage who would end this support after completing college and after completing
high school is 6%.
(i) What is the percentage of parents who would end financial support after a child completes college.
(ii) What is the percentage of parents who would end financial support after a child completes high school.
(iii) What is the total combined percentage of parents who would end financial support after a child completes high
school and after getting a full time job?
OR
What is the total combined percentage of parents who would end financial support after a child completes
college and after getting married?
(i) 5x – 4y + 8 = 0, 7x + 6y – 9 = 0
(ii) 9x + 3y + 12 = 0, 18x + 6y + 24 = 0
(iii) 6x – 3y + 10 = 0, 2x – y + 9 = 0
𝑎 𝑏 𝑐1
2. On comparing the ratios 𝑎1 , 𝑏1 and find out whether the following pair of linear equations are consistent, or inconsistent.
2 2 𝑐2
9. Five years hence, the age of Jacob will be three times that of his son. Five years ago, Jacob’s age was seven times that of his
son. What are their present ages?
10. The sum of the digits of a two-digit number is 9. Also, nine times this number is twice the number obtained by
reversing the order of the digits. Find the number.
11. Meena went to a bank to withdraw ₹ 2000. She asked the cashier to give her ₹50 and ₹100 notes only. Meena got
25 notes in all. Find how many notes of ₹ 50 and ₹ 100 she received.
12. A lending library has a fixed charge for the first three days and an additional charge for each day thereafter. Sarita paid ₹
27 for a book kept for seven days, while Susila paid ₹ 21 for the book she kept for five days. Find the fixed charge and the
charge for each extra day.
ADDITIONAL QUESTIONS
1. Solve graphically the system of linear equations 4x – 5y + 16 = 0 and 2x + y – 6 = 0. Determine the vertices of the triangle
formed by these lines and the x-axis and find the area of the triangle so formed.
2. Solve the following system of linear equations graphically: 4x – 5y – 20 = 0 and 3x + 5y – 15 = 0.Determine the vertices of the
triangle formed by the lines representing the above equations and the y-axis.
3. Solve for x and y: 0.4x – 1.5y = 6.5, 0.3x – 0.2y = 0.9.
4. Find the values of k for which the system of equations x – 2y = 3, 3x + ky =1 has a unique solution.
5. Find the value of k for which the following pair of linear equations has infinitely many solutions:
2x – 3y = 7, (k + 1)x + (1 – 2k)y = (5k – 4) .
6. Find the values of k for which the pair of linear equations kx + 3y = k – 2 and 12x + ky = k has no solution.
7. Find the values of k for which the system of equations kx – y = 2, 6x – 2y = 3 has (i) a unique solution, (ii) no solution. (iii) Is there a
value of k for which the given system has infinitely many solutions?
8. The sum of the digits of a two-digit number is 12. The number obtained by interchanging its digits exceeds the given number by 18.
Find the number.
HOTS QUESTIONS
1. If a bag containing red and white balls, half the number of white balls is equal to one-third the numbers of red balls. Thrice the
total number of balls exceeds seven times the number of white balls by 6. How many balls of each colour does the bag contain?
2. A and B are two points 150 km apart on a highway. Two cars start A and B at the same time. If they move in the same direction they
meet in 15 hours. But if they move in the opposite direction, they meet in 1hour. Find their speeds.
3. Find the value of x and y: 99x + 101y =499
101x + 99y =501
4. In the figure below ABCDE is a pentagon with BE || CD and BC || DE. BC is perpendicular to DC. If the perimeter of ABCDE is 21
cm, find the values of x and y.
5. It can take 12 hours to fill a swimming pool using two pipes. If the pipe of larger diameter is used for 4 hours and the pipe of
smaller diameter for 9 hours only half the pool can be filled. How long would it take for each pipe to fill the pool separately?
6. Find the value of x and y of the following pair of linear equation and justify your answer.
2ax + by =a, 4ax + 2by -2a =0; a, b≠ 0
ANSWERS
MCQ
1. (i) (a) 70, (ii) (c) 30 (iii) (b) 1750 OR (d) 2150
2. (i) (c) 28% (ii) (a) 22% (iii) (c) 52% OR (d) 34%
ADDITIONAL QUESTION
1. Vertices are (1, 4), (–4, 0) and (3, 0), 14 sq. unit
2. (0, –4), (0, 3) and (5, 0).
3. x = 5 and y = –3.
4. All real values of k, other than –6.
5. k = 5
6. k = 6 or k = – 6.
7. (i) k ≠ 3, (ii) k =3, (iii) no real value of k
8. 57
HOTS QUESTIONS
1. Let the number of red balls be x and white balls be yAccording to the question,
2x - 3y = 0 (1)
And 3(x + y) – 7y = 6
3x - 4y = 6 (2)
Solving (1) from (2) we have
y = 12 and x = 18
Hence, number of red balls = 18 and number of white balls = 12
5. The pipe of larger diameter alone can fill the pool in 20 hours and the pipe of smaller diameter alone can fill the pool in 30 hours.
6. Many solutions
Chapter 4
QUADRATIC EQUATIONS
An equation of the form p(x) =0, where p(x) is a quadratic polynomial (polynomial of degree 2) is a called quadratic equation.
In general form, ax2 + bx + c = 0, a ≠ 0 is a quadratic equation in variable x.
SOLUTION OF A QUADRATIC EQUATION
Roots of the quadratic equation ax2 + bx + c = 0 are called the solutions of the quadratic equation. Solutions of a Quadratic Equation
can be found by using following methods:
(i) By Factorisation Method: To find the solution of a quadratic equation by factorisation method, first represent the given
equation as a product of two linear factors by splitting the middle term or by using identities and then equate each of the factor equal
to zero to get the desired roots.
(ii) By Quadratic Formula: For a quadratic equation ax2 + bx + c = 0, we have
−𝒃±√𝐃
x= , where D (∆) = b2 - 4ac and D is called discriminant of the quadratic equation.
𝟐𝒂
The following cases arise:
i. If D = b2 - 4ac>0 then the roots of the equation are real and distinct.
−𝒃
ii. If D = b2 - 4ac=0 then roots of the equation are equal and real. α= β= 𝟐𝒂
iii. If D = b2 - 4ac<0 then there does not exist any real root.
iv. If D = b2 - 4ac>0 and perfect square, then the roots are real (rational) and unequal.
v. If D = b2- 4ac > 0 and not a perfect square, then the roots are real(irrational) and unequal
QUADRATIC EQUATION WHEN THE ROOTS ARE GIVEN
The quadratic equation whose roots are a and b is given as x2 - (a +b) x +ab = 0
Answer
MCQ / ASSERTION
Q1. (b) Q2. (c)Q3. (d)Q4. (d)Q5. (c)Q6. (d)Q7. (c)Q8. (a)Q9. (d)Q10. (a)
2MARKS QUESTIONS
Q11. Sum of roots = product of roots
-6/p = 4p/p
p=-3/2
Q17. Let the smaller tap fill the tank in x hr and the tap with larger diameter fill the tank in x-10 hr
ATQ
1 1 8
+ =
𝑥 𝑥−10 75
4x2 -115x+375=0
X = 15/4, 25 (15/4 not possible)
Smaller diameter tap fill in 25 hours and larger diameter tap fill in 15 hrs.
5 MARKS QUESTIONS
Q18. Side of 1st square is x cm and side of 2nd square is x+6 cm
ATQ
x +( x+6)2 = 468
2
x2 +6x-432=0
x= -18, 12 (negative value ignored)
Side of 1st square 12cm and side 2nd square is 18cm
Q19. Let present age of son is x years and father age is 2x2
ATQ
2x2 -3x-20=0
X=4, -5/2 (age cannot be negative)
Present age of son is 4 year and father age is 32years
1 1 1 1
Q20.𝑎+𝑏+𝑥 - = 𝑎 +𝑏
𝑥
x2+(a+b)x + ab =0
x = -a, -b
CASE BASED STUDY
Q21. (a) 225km (b) x2+5x-1800 (c) 9 hours or 8 hours
Q22. (a) 12km/h (b) x2+48x-324 (c) 6km/h or 1 hour
Q23. (a) 2x2-19x+24 (b) width = 4m or length 9 m (c) 14m2
Things to remember:
Standard form of an AP is given as: a, a+d, a+2d, a+3d...., where a is the first term and d is the common difference.
nth term 𝒂𝒏 of the AP with first term a and common difference d is given by 𝒂𝒏 = a+ (n-1)d
nth term from the end of an AP is given by: an=l - (n-1)d , where l is the last term of A.P., d is the common difference and an is
the nth term
𝒂+𝒄
Arithmetic mean : b = , where a, b, c are in A.P. and b is arithmetic mean
𝟐
23. If m times the mth term of A.P. is equal to n times of nth term and m≠n, show that (m+n)th term of the A.P. is 0.
[Hint: step 1: m (am) = n (an); step 2: m{ a + (m-1)d} = n{ a + (n-1)d}]
24. A man repays a loan of ₹ 3250 by paying ₹ 20 in the first month and then increases the payment by ₹ 15 every month. How long
will it take him to clear the loan? (Hint: 𝒏𝟐{2x20+(n-1)15} = 3250)
25. A thief runs with a uniform speed of 100 m/minute. After one minute a policeman runs after the thief to catch him. He goes with a
speed of 100m/minute in the first minute and increased his speed by 10 m/minute every succeeding minute. After how many
minutes the policeman will catch the thief. Hint: [distance = 100(n +1) = 𝒏𝟐 {2 x 100+(n-1)10}]
26. A sum of ₹ 1000 is to be used to give five cash prizes to students of a school for their overall academic performance. If each prize
is ₹ 50 less than its preceding prize, find the value of each of the prizes
27. A contract on construction job specifies a penalty for delay of completion beyond a certain date as follows: ₹250 for the first day,
₹ 300 for the second day, ₹ 350 for the third day, etc., the penalty for each succeeding day being ₹ 50 more than for the preceding
day. How much money the contractor has to pay as penalty, if he has delayed the work by 30 days?
Case Study Based Questions
28. Seating Capacity:
The Fox Theatre creates a “theatre in the round” when it shows any of Rabindranath Tagore’s plays. The first row has 80 seats,
he second row has 88, the third row has 96, and so on.
(i) How many seats are in the 10th row?
(ii) How many seats are in the 25th row?
(iii) If there is a room for 25 rows, how many chairs will be needed to set up the theatre?
Or
How many people can sit in the second last row?
29. Contest Prizes:
A contest offers 15 prizes. The 1st prize is ₹ 5000, and each successive prize is ₹ 250 less than the preceding prize.
(i) What is the value of the 15th prize?
(ii) What is the total amount of money distributed in prizes?
(iii) What is the sum of first and last prize?
OR
By how much does the amount for 1st prize exceed the amount for the 6th prize?
30. Increasing Salary:
A teacher has a salary of ₹ 8,00,000 during the first year and gets an increment of ₹ 5000 each year.
(i) What will be his salary in the seventh year?
(ii) What is the total salary for 7 years of work for the teacher?
(iii) What is the difference of the salary of 7th year and 2nd year?
OR
What will be his salary after 10 years of service? ( Hint: find 11th term)
31. Let us practice Piano :
Suppose you practice the piano 45 min on the first day of the semester and increase your practice time by 5 min each day.
(i) How much total time will you devote to practicing during the first 15 days of the semester? (ii) How much time will you
devote to practicing during the 35th day of the semester?
(iii) How can you relate music with Mathematics?
Or
Write one benefit of learning music.
Answers:
1. b 2. c 3. c 4. a 5. a
6. a 7. a 8. b 9. c 10. b
11. 27 12. 15 13. 3, 5, 7, 9 14. 330 15. 3,5,7,9
16. √𝟗𝟔 17. d = -1/5, n= 27 18. Refer hint 19. -6 20. 1170
21. 2, 6, 10,14 or 14, 22. 16 rows, 5 logs 23. Refer hint 24. 20 months 25. 5 min
10,6,2
26. 300, 250, 200, 150, 100 27. ₹ 29250 28. i. 152 29.i. ₹1500 30. i. ₹8,30, 000
ii. 272 ii. ₹48750 ii. ₹ 57, 05, 000
iii. 4400
iii. ₹3500 iii. ₹ 25000
264 people
₹1250 ₹ 850000
31.i. 20 hours 32. i. 176
ii. 215 min ii. 576
iii. open ended answer iii. 240 feet
64 feet
CHAPTER 6 (Triangles)
Similar Triangles: Two triangles are said to be similar if their corresponding angles are equal and their corresponding
sides are proportional.
Criteria for Similarity: In ΔABC and ΔDEF
(i) AAA Similarity: ΔABC ~ ΔDEF when
∠A=∠D, ∠B=∠E and ∠C=∠F
(ii) SAS Similarity:
ΔABC~ΔDEF when
∠A=∠D and AB/DE=AC/DF
(iii) SSS Similarity: ΔABC ~ ΔDEF if: AB/DE = AC/DF = BC/EF
Basic Proportionality Theorem: If a line is drawn parallel to one side of a triangle to intersect the other two sides
in distinct points, the other two sides are divided in the same ratio.
S.NO. QUESTIONS
1 If in two triangles Δ DEF and Δ PQR, ∠D = ∠Q and ∠R = ∠E, then which of the following is not true?
(a) EF/PR = DF/PQ (b) DE/PQ = EF/RP (c) DE/QR = DF/PQ (d) EF/RP = DE/QR
2 If ΔABC ~ ΔEDF and ΔABC is not similar to ΔDEF, then which of the following is not true?
(a) BC . EF = AC . FD (b) AB . EF = AC . DE (c) BC . DE = AB . EF (d) BC . DE = AB . FD
3 D and E are respectively the points on the sides AB and AC of a triangle ABC such that AD = 2 cm, BD = 3 cm, BC = 7.5
cm and DE || BC. Then, length of DE (in cms) is:
(a) 2.5 (b) 3 (c) 5 (d) 6
4 A vertical pole of length 6 m casts a shadow 4 m long on the ground and at the same time a tower casts a shadow 28
m long. Find the height of the tower (in m).
(a) 42 (b) 32 (c) 5 (d)16
5 In this figure if DE || BC. Then find the value of x :
(a) 10 (b) 11 (c) 12 (d)13
6 In Δ ABC, D and E are mid-points of AC and BC respectively such that DE || AB. If AD = 2x, BE = 2x – 1,
CD = x + 1 and CE = x – 1, then find the value of x:
7 Students of a school decided to participate in ‘Save girl child’ campaign. They decided to decorate a
triangular path as shown. If AB = AC and BC2 = AC × CD, then prove that BD = BC.
8 The perimeters of two similar triangles are 25 cm and 15 cm respectively. If one side of the first triangle is 9 cm, find
the corresponding side of the second triangle.
9 In ΔABC, D and E are points on the sides of AB and AC such that DE || BC. If AD = 2.5 cm, BD =3 cm, AE = 3.75 cm, find the
length of AC.
10 Prove that a line drawn through the mid-point of one side of a triangle parallel to another side bisects the third side.
11 ABCD is a trapezium in which AB || DC and its diagonals intersect each other at the point O. Show that 𝐴𝑂/𝐵𝑂 = 𝐶𝑂/𝐷𝑂
12 Diagonals AC and BD of a trapezium ABCD with AB || DC intersect each other at the point O.
Using a similarity criterion for two triangles, show that OA/OC=OB/OD∙
13 In the given figure, altitudes AD and CE of ∆ABC intersect each other at the point P.
Show that:
(i) ∆AEP ~ ∆CDP
(ii) ∆ABD ~ ∆CBE
(iii) ∆AEP ~ ∆ADB
(iv) ∆PDC ~ ∆BEC
14 In the given figure, ABC and AMP are two right triangles, right angled at B and M respectively. Prove that:
(i) ∆ABC~ ∆AMP
(ii)CA/PA = BC/MP
15 CD and GH are respectively the bisectors of ∠ACB and ∠EGF such that D and H lie on sides AB and FE of ∆ABC and
∆EFG respectively. If ∆ABC ~ ∆FEG, show that
(i) ∆DCB~ ∆HGE (ii) C D / G H = A C / F G
16 Sides AB and BC and median AD of a triangle ABC are respectively proportional to sides PQ and QR and median PM
of ∆PQR. Show that ∆ABC ~ ∆PQR.
17 State and prove Basic proportionality theorem.
HOTS QUESTIONS
1. In Fig , OB is the perpendicular bisector of the line segment DE, FA ⊥ OB and FE intersects OB at the point C.
Prove that: (1/ OA) + (1/ OB) = 2/ OC
2. In the figure, ABCD is a parallelogram and E divides BC in the ratio 1: 3. DB and AE intersect at F.
Show that DF = 4 FB and AF = 4 FE.
4. Sides AB and AC and median AD of a triangle ABC are respectively proportional to sides PQ and PR and median PM of another triangle
PQR. Show that ∆ ABC ~ ∆ PQR
CASE STUDY BASED QUESTIONS:
1) CASE STUDY
In the hot Indian summers, we are all glad to have the trees and their shade. But do you know how shadows are formed? Shadows are
formed when light, for example, sunlight, falls on opaque objects. Consider the shadows of two trees A and B. The shadow of two trees
A and B formed at 6 pm on a particular day is given in the diagram.
The height of tree A is 5m and the height of tree B is 7m. The length of the shadow of tree B is 21m.
1) What is the length of the shadow of tree A?
2) What concept is used for finding the height of the tree?
3) What is the value of x.
Q1. If the length of the model is 11cm, then what is the overall length of the engine in the photograph above,
including the couplings (mechanism used to connect)?
Q2. What is the actual width of the door if the width of the door in photograph is 0.35cm?
Q3. The length of AB in the given figure:
3. CASE STUDY
Vijay is trying to find the average height of a tower near his house.
He is using the properties of similar triangles.
The height of Vijay’s house if 20m when Vijay’s house casts a shadow 10m long on the ground.
At the same time, the tower casts a shadow 50m long on the ground and the house of Ajay casts 20m .
shadow on the ground.
1. What is the height of the tower?
2. What will be the length of the shadow of the tower when Vijay’s house casts a shadow of 12m?
3. What is the height of Ajay’s house?
.
4. CASE STUDY
Mountaineering is the perfect activity for adventure lovers.
Every year, several mountaineers attempt to climb the Mount Everest.
The path of two mountaineers from the base camps B and C are shown above.
D and E are two mid camping areas in between their paths.
The line joining D and E is parallel to the line joining B and C.
1) Find the distance between E and C.
2) What is the ratio of the distance between DE and BC?
3) If AD/DB= 5/9 and EC = 180 m then find AE.
ASSERTION REASONING QUESTIONS
DIRECTION :
In the following questions a statement of Assertion (A) is followed by a statement of Reason (R).
Choose the correct option as:
1) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
2) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
3) Assertion (A) is true but reason (R) is false.
4) Assertion (A) is false but reason (R) is true.
1. Assertion: D and E are points on the sides AB and AC respectively of a ΔABC such that DE║BC then the value of
x is 4, when AD = x cm, DB = (x – 2) cm, AE = (x + 2) cm and EC = (x – 1) cm.
Reason: If a line is parallel to one side of a triangle, then its divides the other two sides in the same ratio.
2. Assertion (A): E and F are points on the sides PQ and PR respectively of a triangle PQR, if PQ = 1.28 cm, PR = 2.56 cm, PE = 0.18 cm and
PF = 0.36 cm, then, EF || QR by converse of BPT.
Reason (R): Converse of basic proportionality theorem states that if a line divides any two sides of a triangle in the
same ratio, then the line is parallel to the third side.
3. Assertion (A): If ΔABC & ΔPQR are congruent triangles, then they are also similar triangles.
Reason (R): All congruent triangles are similar but the similar triangles need not be congruent.
4. Assertion (A): In the given fig. PA || QB || RC || SB
Reason (R ) : If three or more line segments are perpendicular to one line , then they are parallel to each other.
ANSWERS:
1) B 2) C 3) B 4) A 5) B
6) x=1/3 7) correct proof 8)DE=5.4cm 9) AC=8.25cm
Hots Questions
1.(Hint) ΔOFA ~ ΔODB
∠A = ∠B=90
2. (Hint) ΔADF ~ ΔEBF by AA
3. (Hint) DE || BC by converse of BPT
∠1= ∠3, ∠2 = ∠4 corresponding angles
Case study
1. (i) 15m (ii) similarity of triangle (iii) x = 2, -5 (neglect negative value)
SECTION - B
1. The values of y, for which the distance between the points P(2,-3) and Q(10,y) is 10 units, are:
(a) 9, 6 (b) 3, -9 (c) -3, 9 (d) 9, -6
2. The perpendicular bisector of the line segment joining the points A (1, 5) and B (4, 6) cuts the y-axis at:
(a) (0, 13) (b) (0, –13) (c) (0, 12) (d) (13, 0)
3. A line intersects the Y-axis and X-axis at the points P and Q, respectively. If (2, - 5) is the mid-point of PQ, then the
coordinates of P and Q are respectively:
(a) (0, -5) and (2, 0) (b) (0, 10) and (- 4, 0) (c) (0, 4) and (- 10, 0) (d) (0, – 10) and (4, 0)
4. The point on X- axis which is equidistant from (2, -5) and (-2, 9) is:
(a) (–2,7) (b) (-7,0) (c) (–1,0) (d) (7,0)
5. In what ratio the line x – y – 2 = 0 divides the line segment joining (3, –1) and (8, 9)?
(a)1: 2 (b) 2: 1 (c) 2: 3 (d) 1: 3
6. The fourth vertex D of a parallelogram ABCD whose three vertices are A (–2, 3), B (6, 7) and C (8, 3) is:
(a) (0, 1) (b) (0, –1) (c) (–1, 0) (d) (1, 0)
7. The distance between A (a + b, a – b) and B (a – b, -a – b) is:
(a) 2a+2b (b) 2√(a2 + b2) (c) 2a (d)a2 - b2
8. The line segment joining the points (3, -1) and (-6, 5) is trisected. The coordinates of point of trisection are
(a) (0,1)(3, 3) (b) (0, 1)(- 3, 3) (c) (1, 0)(3, – 3) (d) (1, 0)(-3, -3)
9. The line 3x + y – 9 = 0 divides the line joining the points (1, 3) and (2, 7) internally in the ratio:
(a) 3: 4 (b) 3: 2 (c) 2: 3 (d) 4: 3
10. The coordinates of the centroid of a triangle whose vertices are (0, 6), (8,12) and (8, 0) is:
(a) (4, 6) (b) (16, 6) (c) (8, 6) (d) (16/3, 6)
11. The distance between (0, sin𝜃) and (-cos𝜃, 0) is:
(a) 0 (b)-1 (c) sin𝜃. 𝑐𝑜𝑠𝜃 (d) 1
12. If (a/3, 4) is the mid-point of the segment joining the points P (-6, 5) and R(-2, 3), then the value of ‘a’ is:
(a)12 (b) -6 (c) -12 (d) -4
13. The points (1,1), (-2, 7) and (3, -3) are:
(a) vertices of an equilateral Δ (b) collinear (c) vertices of an isosceles Δ (d) None of these
14.The perimeter of a triangle with vertices (0, 4), (0, 0) and (3, 0) is:
(a) 5 (b) 12 (c) 11 (d) 7
14. The coordinates of the point P dividing the line segment joining the points A(1,3), and B(4,6) in the ratio 2:1 is:
(a) (2,4) (b) (3,5) (c) (4,2) (d) (5,3)
Assertion- Reason Questions:
Direction for questions 1 & 5: In question numbers 1 and 5, a statement of Assertion (A) is followed by a statement of Reason (R).
Choose the correct option.
A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
B. Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
C. Assertion (A) is true but Reason (R) is false.
D. Assertion(A) is false but Reason (R) is correct.
1. Assertion: if the coordinate of the mid-points of sides AB and AC of triangle ABC are D(3,5) and E(-3,-3) respectively then
BC= 20 units
Reason: The line segment joining the mid points of two sides of a triangle is parallel
2. Assertion: The perimeter of ΔAOB where O is origin, A(3,0), B(0, 4) is 7 units.
Reason: Perimeter of a triangle is the sum of all three sides of the triangle.
3. Assertion: Three points A, B, C are such that AB + BC > AC, then they are collinear.
Reason: Three points are collinear if they lie on a straight line.
4. Assertion :The distance point P(2,3) from the x-axis is 3.
Reason: The distance from x-axis is equal to its ordinate.
HOTS
1. The mid-points D , E , F of sides AB , BC , and CA respectively of the sides of a triangle ABC are D(3,4) , E (8,9) and F (6,7).
Find the coordinates of the vertices of the triangle.
2. If the mid-points of the line segment joining the points A(3,4) and B(k,6) is P(x, y) and x+y-10=0, find the value of k.
3. Name the type of triangle PQR formed by the points P (√𝟐, √𝟐) , Q(−√𝟐, −√𝟐) and R (−√𝟔, √𝟔).
4. If P(𝟗𝒂 − 𝟐 , −𝒃) divides line segment joining A(𝟑𝒂 + 𝟏, −𝟑) and B (𝟖𝒂, 𝟓) in the ratio 3:1 , find the values of a and b.
5. Find the ratio in which the point (x, 1) divides the line segment joining the points (-3,5) and (2,-5). Also find the value of x.
SECTION A SECTION B
Question Answer Question Answer
1 (b) 5 1 (b) 3,-9
2 (b) √34 2 (a) (0,13)
3 (c) (-1, 2) 3 (d)(0,-10) &(4,0)
4 (d) IV quadrant 4 (b) (-7,0)
5 (c)10 5 (c)2:3
6 (d) 5 6 (b) (0, -1)
7 (c) 2:7 7 (b)
8 (d) (0, 0) 8 (0,1) (-3,3)
9 (b) 2 9 (a) 3:4
10 (b) 3 10 (d) (16/3,6)
11 (b) (2, 0) 11 (d) 1
12 (c)-12
13 (b) collinear
14 (b) 12
15 (b) (3,5)
Hot’s answers:
1. By mid-point theorem DFEB is a parallelogram. Let coordinates of B is (x,y)
X=3+8-5=5 and y=4+9-7=6. So B is (5,6). Similarly A(1,2) and C (11,12)
𝟑+𝒌 𝟑+𝒌
2. mid point is ( , 𝟓) = (𝒙, 𝒚) then x= and y=5 using x+y-10=0 get k=7.
𝟐 𝟐
3. PQ=PR=RQ=4 units. Triangle PQR is equilateral triangle.
4. By using section formula a=1 and b= -13/4.
5. k=3/2,or x=0
Chapter 8
Introduction to Trigonometry
Important points:
Sometimes we observe imaginary triangle in nature,
e.g. if we look at the top of a tower , a right angle can be imagined. As shown in figure
We need to find height BC or distance AB or AC.
These all can be found by using mathematical techniques which comes under a branch ofmathematics called Trigonometry.
Consider a right angled triangle ABC right angled at B.
Fig 1
Observing the above two triangles we see that one side i.e. hypotenuse (longest side of right triangle) is fixed it is opposite to right
angle, but other sides varies in respect of angle under consideration. Here it is to note that we write:
Side opposite to given angle as PERPENDICULAR (P), Side adjacent to given angle as BASE (B)
And the longest side HYPOTENUSE (H).
TRIGONOMETRIC RATIOS
𝒔𝒊𝒅𝒆 𝒐𝒑𝒑𝒐𝒔𝒊𝒕𝒆 𝒕𝒐 ∠𝑨 BC
𝒔𝒊𝒏 𝒐𝒇 ∠𝑨 = 𝐡𝐲𝐩𝐨𝐭𝐞𝐧𝐮𝐬𝐞
= AC
𝒔𝒊𝒅𝒆 𝒐𝒑𝒑𝒐𝒔𝒊𝒕𝒆 𝒕𝒐 ∠𝑨 BC
𝒕𝒂𝒏𝒈𝒆𝒏𝒕 𝒐𝒇 ∠𝑨 = =
𝒔𝒊𝒅𝒆 𝒂𝒅𝒋𝒂𝒄𝒆𝒏𝒕 𝒕𝒐 ∠𝑨 AB
𝟏 AC
𝒄𝒐𝒔𝒆𝒄𝒂𝒏𝒕 𝒐𝒇 ∠𝑨 = =
𝐬𝐢𝐧𝐞 𝐨𝐟 ∠𝑨 BC
𝟏 AC
𝒔𝒆𝒄𝒂𝒏𝒕 𝒐𝒇 ∠𝑨 = =
𝐜𝐨𝐬𝐢𝐧𝐞 𝐨𝐟 ∠𝑨 AB
𝟏 AB
𝒄𝒐𝒕𝒂𝒏𝒈𝒆𝒏𝒕 𝒐𝒇 ∠𝑨 = =
𝐭𝐚𝐧𝐠𝐞𝐧𝐭 𝐨𝐟 ∠𝑨 BC
TRIGNOMETRIC TABLE
0° 30° 45° 60° 90°
sin 0 1/2 1/√𝟐 √𝟑/𝟐 1
cos 1 √𝟑/𝟐 1/√𝟐 1/2 0
tan 0 1/√𝟑 1 √𝟑 Not Defined
cot Not Defined √𝟑 1 1/√𝟑 0
sec 1 2/√𝟑 √𝟐 2 Not Defined
cosec Not Defined 2 √𝟐 2/√𝟑 1
QUESTIONS
s.no
1 If x = 2 sin2𝜃 and y=2cos2 𝜃 +1 then x + y is equal to
(a) 3 (b) 2 (c) 1 (d) 0
2. Given in ∆ABC right angled at B, If tan A = 4/3, then the value of cos C is
(a) 3/4 (b)4/5 (c) 1 (d) none of these
3. In ∆OPQ, right-angled at P, OP = 7 cm and OQ - PQ = 1 cm, then the values of sin Q.
(a)7/25 (b) 24/25 (c) 1 (d) none of these
4. Given in ∆ABC right angled at B, 15 cot A = 8, then sin C =
(a) 0 (b) 8/17 (c) 1 (d) none of these
5. In ∆PQR, right-angled at Q, PR + QR = 25 cm and PQ = 5 cm, then the value of sin P is
5 12 13
(a) 13 (b) 13 (c) 12 (d) 0
6. 1
If 𝐶𝑜𝑠𝜃=2 then𝑪𝒐𝒔𝜽 − 𝑺𝒆𝒄𝜽 is equal to:
1 1 1 2
(a) −1 2 (b) − 2 (c) 1 2 (d) 3
8. 3
If cos A = 5 ,find the value of 9 +9 tan2 A :
9 25 1
(a) 25 (b) 25 (c) (d)
9 25
9. 3
If 3𝑥 = 𝑠𝑒𝑐𝜃 and𝑥 = 𝑡𝑎𝑛𝜃 , then 9(𝑥 2 − 𝑥 2 ) is :
1
1
(a) 9 (b) 3 (c) (d) 1
9
10. If sin(𝐴 − 𝐵) =
1 1
𝑎𝑛𝑑 cos(𝐴 + 𝐵) = 2 , 𝑡ℎ𝑒𝑛 𝑡ℎ𝑒 𝑣𝑎𝑙𝑢𝑒 𝑜𝑓 𝐵 𝑖𝑠:
2
(a) 45° (b) 60° (c) 15° (d) 0°
11. Assertion: The value of sin600 cos300 + sin300 cos600 is 1.
Reason: sin900=1 and cos900=0
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason(R) is false.
(d) Assertion (A) is false but reason(R) is true.
12. Assertion: In a right ∆ABC, right angled at B, if tanA=1, then 2sinA.cosA=1
Reason: cosec A is the abbreviation used for cosecant of angle A.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
Assertion: sin(A+B)=sin A + sin B
13.
Reason: For any value of 𝜃, 1+tan2 𝜃 = sec2 𝜃
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason(R) is false.
(d) Assertion (A) is false but reason (R) is true.
14. Assertion:- sin252° + 𝑐𝑜𝑠 2 52° = 1
Reason:- For any value of 𝜽, sin2𝜃 + 𝑐𝑜𝑠 2 𝜃 = 1
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true
15. 𝟓
Assertion:-The value of𝒄𝒐𝒔𝜽 = 𝟑 , is not possible.
Reason: - In a right-angled triangle, hypotenuse is the largest side.
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
16. If 3cot A = 4, find the value of (cosec2 A + 1)/( cosec2 A - 1).
17. If tan (3x - 15°) = 1 then find the value of x.
18. 2𝑡𝑎𝑛𝐴
In a right ∆𝐴𝐵𝐶, right angled at B, the ratio of AB to AC is 1:√2. Find the value of 1+𝑡𝑎𝑛2𝐴.
19. Evaluate sin 60° cos 30° + sin 30° cos 60°.
20. Evaluate 2tan2 45° + cos2 30° - sin2 60°.
21. If secθ + tan θ = p, then find the value of cosecθ.
22. 𝑡𝑎𝑛𝜃−𝑐𝑜𝑡𝜃
Prove that 𝑠𝑖𝑛𝜃𝑐𝑜𝑠𝜃 = 𝑡𝑎𝑛2 𝜃 − 𝑐𝑜𝑡 2 𝜃
Angle of Depression
Long Answers
11. A man standing on the deck of a ship, 10 m above the water level observes the angle of elevation of the top of a hill as 60° and
angle of depression the bottom of a hill as 30°. Find the distance of the hill from the ship and height of the hill. (√3 = 1.732)
12. A bird is sitting on the top of a tree, which is 80 m high. The angle of elevation of the bird, from a point on the ground is 45°.
The bird flies away from the point of observation horizontally and remains at a constant height. After 2 seconds, the angle of
elevation of the bird from the point of observation becomes 30°. Find the speed of flying of the bird. (√3 = 1.732)
13. The shadow of a tower standing on a level ground is found to be 40 m longer when the Sun's altitude is 30° than when it is 60°.
Find the height of the tower
14. The angles of depression of the top and the bottom of an 8 m tall building from the top of a multi storeyed building are 30° and
45°, respectively. Find the height of the multi storeyed building and the distance between the two buildings.
15. From a point on a bridge across a river, the angles of depression of the banks on opposite sides of the river are 30° and 45°,
respectively. If the bridge is at a height of 3 m from the banks, find the width of the river.
16. From the top of a 7 m high building, the angle of elevation of the top of a cable tower is 60° and the angle of depression of its
foot is 45°. Determine the height of the tower.
17. A straight highway leads to the foot of a tower. A man standing at the top of the tower observes a car at an angle of depression
of 30°, which is approaching the foot of the tower with a uniform speed. Six seconds later, the angle of depression of the car is
found to be 60°. Find the time taken by the car to reach the foot of the tower from this point.
Case Study Questions
18. A hot air balloon is a type of aircraft. It is lifted by heating the air inside the balloon, usually with fire. Hot air weighs less than
the same volume of cold air (it is less dense), which means that hot air will rise up or float when there is cold air around it, just
like a bubble of air in a pot of water. The greater the difference between the hot and the cold, the greater the difference in
density, and the stronger the balloon will pull up.
Lakshman is riding on a hot air balloon. After reaching at height x at point P, he spots a lorry parked at B on the ground at an
angle of depression of 30°. The balloon rises further by 50 metres at point Q and now he spots the same lorry at an angle of
depression of 45° and a car parked at C at an angle of depression of 30°.
(i) What is the relation between the height x of the balloon at point P and distance d between point A and B?
(ii) When balloon rises further 50 meters, then what is the relation between new height y and d?
(iii) What is the new height of the balloon at point Q?
OR
What is the distance AB on the ground?
19. Observe the picture.
From a point A, h m above from water level, the angle of elevation of top of Chhatri (point B) is 45° and angle of depression of
its reflection in water (point C) is 60°. If the height of Chhatri above water level is (approximately) 10 m, then
(i) Draw a well-labelled figure based on the above information;
(ii) Find ∠ BAC
(iii) Find the height (h) of the point A above water level.
OR
Find distance AB.
20. To explain how trigonometry can be used to measure the height of an inaccessible object, a teacher gave the following example
to students: A TV tower stands vertically on the bank of a canal. From a point on the other bank directly opposite the tower,
the angle of the elevation of the top of the tower is 60° . From another point 20 m away from this point on the line joining this
point to the foot of the tower, the angle of elevation of the top of the tower is 30° (as shown in Figure).
Based on the above, answer the following questions:
(i) The width of the canal is
(ii) The angle formed by the line of sight with the horizontal when it is above the horizontal line is known as?
(iii) Find the height of the tower.
OR
Find the distance of the foot of the tower from the point D
21. A group of students of class X visited India Gate on an educational trip. The teacher and
students had interest in history as well. The teacher narrated that India Gate, official name Delhi Memorial, originally called
All-India War Memorial, monumental sandstone arch in New Delhi, dedicated to the troops of British India who died in wars
fought between 1914 and 1919. The teacher also said that India Gate, which is located at the eastern end of the Kartvaya-Path
(formerly called the Rajpath), is about 138 feet (42 metres) in height.
(i)What is the angle of elevation if they are standing at a distance of 42m away from
the monument?
(ii) They want to see the tower at an angle of 60°. So, they want to know the distance where they should stand and hence find
the distance.
(iii) If the altitude of sun is 60° then find the height of vertical tower that will cast a shadow of length 20 m.
OR
If the altitude of sun is 45° then find the height of vertical tower that will cast a shadow of length 20 m
23 Assertion: If the length of shadow of a vertical pole is equal to its height, then the angle of
elevation of the sun is 45°.
Reason: According to Pythagoras theorem 𝒉𝟐 = 𝒍𝟐 + 𝒃𝟐 , where h = hypotenuse, l = length and b = base.
A. Both assertion (A)and reason (R) are true and reason (R) is the correct explanation of assertion (A).
B. Both assertion (A)and reason (R) are true but reason (R) is NOT the correct explanation of assertion (A).
C. Assertion (A) is true but reasons (R) is false.
D. Assertion (A) is false but reasons (R) is true.
A. Both assertion (A)and reason (R) are true and reason (R) is the correct explanation of assertion (A).
B. Both assertion (A)and reason (R) are true but reason (R) is NOT the correct explanation of assertion (A).
C. Assertion (A) is true but reasons (R) is false.
D. Assertion (A) is false but reasons (R) is true.
25 Assertion: If the angle of elevation of Sun, above a perpendicular line (tower) decreases, then the shadow of tower
increases.
Reason: It is due to decrease in slope of line of sight.
A. Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
B. Both assertion (A) and reason (R) are true but reason (R) is NOT the correct explanation of assertion (A).
C. Assertion (A) is true but reasons (R) is false.
D. Assertion (A) is false but reasons (R) is true.
ANSWER
1. B 2. C 3. B 4. C 5. C 6. 50m
7. 45O 8. 30O 9. 100m 10. 25√𝟑 m 11. 17.32m, 12. 29.28 m/sec
40m
13. h=20√𝟑 m 14. 4(3+√𝟑 ) m, 15. 3(√𝟑 +1)m 16. 7(√𝟑 +1) m 17. 3sec
12(√𝟑 + 1) m
18. (i) d = x √𝟑 (ii) d = y (iii) AQ=25(√3 +3)m OR 25(√3 +3)m
19. (i) draw yourself (ii) 105° (iii) 20 - 10√3 m OR Hint: use sin𝜃
20. (i) 10 m , (ii) angle of elevation (iii) 10√𝟑 m OR 30 m
21. (i) 45°, (ii) 14√𝟑 𝒎, (iii) 20√𝟑 m OR 20 m
22. B 23. B 24. A 25. A
Chapter 10 (CIRCLES)
BASIC TERMINOLOGY:
RADIUS: Distance from the centre to any point on the surface of a circle is called “Radius”.
SECANT: A secant to a circle is a line that cuts the circle at two distinct points.
CHORD: A chord is a line segment whose end points lie on the circle itself. Diameter is the longest
chord in a circle.
TANGENT: A tangent to a circle is a line that touches the circle at exactly one point. For every
point on the circle, there is a unique tangent passing through it. The point where the tangent
touches the circle is called “Point of contact”.
Key points:
1. No tangent can be drawn to a circle which passes through a point that lies inside it.
2. When a point of tangency lies on the circle, there is exactly one tangent to a circle that passes through it.
3. When the point lies outside of the circle, there are accurately two tangents to a circle through it.
THEOREMS:
1. The perpendicular from the centre of the circle to a chord bisects the chord.
2. The angle subtended by an arc at the centre of the circle is double the angle subtended by it at the remaining part of the circle.
Q4. (i)If four sides of the quadrilateral ABCD are tangents to a circle , then:
(a)AC+AD=BD+CD (b) AB+CD=BC+AD (c) AB+CD=AC+BC (d)AC+AD=BC+DB
(ii) At one end A of a diameter AB of a circle of radius 5 cm, tangent XAY is drawn to the circle.
The length of the chord CD parallel to XY and at a distance 8 cm from A is:
(a) 4 cm (b) 5 cm (c) 6 cm (d) 8 cm
Q5. AP and AQ are tangents drawn from a point A to a circle with centre O and radius 9 cm. If OA=15 cm, then AP+AQ=
(a) 12cm (b) 18cm (c) 24cm (d) 36cm
Q6. If common tangents AB and CD of two wheels with centre O and O’ intersect at E, then find OEO’=?
(a) a triangle (b) a line (c) an arc (d) none of these
Q8. In two concentric circles, if length of one chord AB touching inner circle is 12cm then find the length of chord CD?
(a) 10cm (b) 15cm (c) 12cm (d) 6cm
Q9. The length of the tangent from a point which is at a distance of 10cm from the centre of the circle having radius 6cm is?
(a) 8cm (b) 10cm (c) 4cm (d)16cm
Q10. i) If AB= 14cm and PE=5cm, then AE=?
(a) 7 cm (b) 8 cm (c) 19 cm (d) 9cm
ii) The distance between two parallel tangents to a circle of radius 5cm is:
(a) 10 cm (b) 11 cm (c) 12 cm (d) 14 cm
Q11. Prove that the tangent at any point of a circle is perpendicular to the radius through the point of contact.
Q12. Prove that the lengths of tangents drawn from an external point to a circle are equal.
Q13. Two tangents TP and TQ are drawn to a circle with centre O from an external point T. Prove that ∠ PTQ = 2 ∠ OPQ.
Q14. PQ is a chord of length 8 cm of a circle of radius 5 cm. The tangents at P and Q intersect at a point T (see Fig). Find the
length TP
Q15. Prove that the tangents drawn at the ends of a diameter of a circle are parallel.
Q16. A quadrilateral ABCD is drawn to circumscribe a circle (see Fig).
Prove that AB + CD = AD + BC
ii) Prove that the intercept of a tangent between two parallel tangents to a circle subtends a right angle at the centre.
Q19. A triangle ABC is drawn to circumscribe a circle of radius 4 cm such that the segments BD and DC into which BC is divided
by the point of contact D are of lengths 8 cm and 6 cm respectively (see Fig.). Find the sides AB and AC.
Q20. Prove that opposite sides of a quadrilateral circumscribing a circle subtend supplementary angles at the centre of the circle.
CASE STUDY BASED QUESTIONS
Q21. A Ferris wheel (or a big wheel in the United Kingdom) is an amusement ride consisting of a rotating upright wheel with
multiple passengers carrying components (commonly referred to as passenger cars, cabins, tubs, capsules, gondolas, or
pods) attached to the rim in such a way that as the wheel turns, they are kept upright, usually by gravity. After taking a ride
in Ferris wheel, Aarti came out from the crowd and was observing her friends who were enjoying the ride. She was curious
about the different angles and measures that the wheel will form.
She forms the figure as given below.
i) Find ∠RSQ.
ii) Find ∠ORP.
iii) If PQ=40 m and OQ=30 m then find PO.
OR
Find ∠RQP.
Q22. A student draws two circles that touch each other externally at point K with centres A and B and radii 6 cm and 4 cm
respectively as shown in the figure:
i) If two circles touch externally, then the number of common tangents that can be drawn is____
ii) Find the length of PA.
iii) Find the length of PQ.
OR
Find the length of QY
Q23. Arun recently bought a gold coin from a jewellery shop. To protect it, he placed the gold coin in a triangular box, The edge
of the triangle touches the gold coin. In mathematical form, the given statement is defined with the adjoining figure such
that BP = 7 cm, CP =4 cm, AQ=5 cm and ∠ OBP =300.
Q27. Assertion: A tangent to a circle is perpendicular to the radius through the point of contact.
Reason: The lengths of tangents drawn from an external point to a circle are equal.
Q28. Assertion:
In Fig. PQ and PR are tangents drawn from an external point P to a circle with centre O. If QPR = 800, then QOR = 100O
Reason: The angle between two tangents drawn from an external point to a circle is supplementary to the angle subtended
by the line segments joining the point of contact to the centre.
Q29. If AB, AC, PQ are tangents in given Fig. and AB = 5 cm, find the perimeter of APQ.
Q30. ∆ABC is right-angled at B such that BC = 6 cm and AB = 8 cm. Find the radius of its incircle.
ANSWERS
Q1) d Q2) b Q 3) a Q4) (i) b (ii) d
Q14) 20/3 cm Q(15 to 18 ) correct proof Q19) AB=15 cm ,AC=13 cm Q20) correct proof
Q21) i) 750 ii) 900 iii) 50 cm OR 750 Q22) (i) 3 (ii) PA=10 cm (iii) PQ=25 cm OR 1cm
7 √3 √3
Q23) (i) 𝑐𝑚 (ii) 49 6 𝑠𝑞. 𝑐𝑚 (iii) AB= 12cm ,BC=11cm ,AC=9 cm ,statement is correct OR 32 cm
3
2. In Fig , a square is inscribed in a circle of diameter d and another square is circumscribing the circle. Is the area of the outer
square four times the area of the inner square? Give reasons for your answer.
3. Find the area of the flower bed (with semi-circular ends) shown in Fig.
2. To find the polluted region in different areas of Varanasi a survey was conducted by the students of class X. It was found that the
shaded region is the polluted region, where O is the centre of the circle.
Based on the above information, answer the following questions.
(i) Find the radius of the circle
(ii) Find the area of the circle.
(iii) If D lies at the middle of arc BC, then find the area of region COD.
OR
Find the Area of the ΔBAC.
3. A brooch is a small piece of jewellery which has a pin at the back so it can be fastened on a dress, blouse or coat. Designs of some
brooch are shown below. Observe them carefully.
Design A: Brooch A is made with silver wire in the form of a circle with a diameter of 28mm. The wire is used for making 4
diameters which divides the circle into 8 equal parts.
Design B: Brooch b is made of two colours – Gold and silver. The outer part is made of Gold. The circumference of the silver
part is 44mm and the gold part is 3mm wide everywhere.
Refer to Design A
i) Find the total length of silver wire required.
ii) Find the area of each sector of the brooch.
Refer to Design B
iii) Find the circumference of outer part (golden).
OR
Find the difference of areas of golden and silver parts.
4. Director of a company select a round glass trophy for awarding their employees on annual function. Design of each trophy is made
as shown in the figure, where its base ABCD is golden plated from the front side at the rate of Rs. 6per cm 2.
Q.1. Assertion (A): In a circle of radius 6 cm, the angle of a sector is 60°. Then the area of the sector is 132/7 cm 2.
Reason (R): Area of the circle with radius r is πr2.
Q.2. Assertion (A): If the circumference of a circle is 176 cm, then its radius is 28 cm.
Reason (R): Circumference = 2π × radius.
Q.3. Assertion (A): If the outer and inner diameter of a circular path is 10 m and 6 m respectively, then area of the path is 16π m2.
Reason (R): If R and r be the radius of outer and inner circular path respectively, then area of circular path = π(R 2 – r2).
Q.4. Assertion (A): The length of the minute hand of a clock is 7 cm. Then the area swept by the minute hand in 5 minute is 77/6 cm 2.
Reason (R): The length of an arc of a sector of angle 𝜃 and radius r is given by l=360
θ
×2πr
ANSWERS
MCQ
1) D 2) C 3) D 4) B 5) A 6) D 7) C
8) B 9) D 10) C 11) C 12) C 13) B 14) C 15) B
MCQ (1MARK)
1. A piece of paper is in the shape of a semi-circular region of radius 10 cm. It is rolled to form a right circular cone. The slant
height is:
(a) 5 cm (b) 10 cm (c) 15 cm (d) 20 cm
2. The total surface area of a solid hemisphere of radius 7 cm is:
(a) 447 cm2 (b) 239 cm2 (c) 174 cm2 (d) 462cm2
3. A cylinder and a cone are of same base radius and of same height. The ratio of the volume of the cylinder to that of the cone is:
(a) 2 : 1 (b) 3 : 1 (c) 2 : 3 (d) 3 : 2
4. A solid formed on revolving a right angled triangle about its height is:
(a) cylinder (b) sphere (c) right circular cone (d) two cones
5. Volumes of two spheres are in the ratio 64:27. The ratio of their surface areas is:
(a) 3 : 4 (b) 4 : 3 (c) 9 : 16 (d) 16 : 9
6. The ratio of the total surface area to the lateral surface area of a cylinder with base radius 80 cm and height 20 cm is:
(a) 1 : 2 (b) 2 : 1 (c) 3 : 1 (d) 5 : 1
7. The radii of the base of a cylinder and a cone are in the ratio 3 : 4 and their heights are in the ratio 2 : 3, then ratio of their
volumes is:
(a) 9 : 8 (b) 9 : 4 (c) 3 : 1 (d) 27 : 64
8. If two cubes, each of edge 4 cm are joined end to end, then the surface area of the resulting cuboid is:
(a) 100 cm2 (b) 160 cm2 (c) 200 cm2 (d) 80 cm2
9. The curved surface area of a cylinder is 264 m and its volume is 924 m . The ratio of its diameter to its height is:
2 3
1. Assertion: Total surface area of the cylinder having radius of the base 14 cm and height 30 cm is 3872 cm 2.
Reason: If r be the radius and h be the height of the cylinder, then total surface area = (2πrh + 2πr 2).
2. Assertion: From a solid cylinder, whose height is 12 cm and diameter 10 cm a conical cavity of same height and same
diameter is hollowed out. Then, volume of the cone is 2200/7 cm3.
3. Reason: If a conical cavity of same height and same diameter is hollowed out from a cylinder of height h and base radius r,
then volume of the cone will be half of the volume of the cylinder.
4. Assertion: If the height of a cone is 24 cm and diameter of the base is 14 cm, then the slant height of the cone is 15 cm.
Reason: If r be the radius and h the slant height of the cone, then slant height = √(h 2+r2)
5. Assertion: If the radius of a cone is halved and volume is not changed, then height remains same.
Reason: If the radius of a cone is halved and volume is not changed then height must become four times of the original height.
2. Water flows through a cylindrical pipe, whose inner radius is 1 cm, at the rate of 80 m/sec in an empty cylindrical tank, the
radius of whose base is 40 cm. What is the rise of water level in tank in half an hour?
3. There are two identical solid cubical boxes of side 7cm. From the top face of the first cube a hemisphere of diameter equal to
the side of the cube is scooped out. This hemisphere is inverted and placed on the top of the second cube’s surface to form a
dome. Find the ratio of the total surface area of the two new solids formed.
4. Water is flowing at the rate of 15 km/h through a pipe of diameter 14 cm into a cuboidal pond which is 50 m long and 44 m
wide. In what time will the level of water in pond rise by 21 cm?
CASE STUDY BASED QUESTIONS
1. The Great Stupa at Sanchi is one of the oldest stone structures in India, and an important monument of Indian Architecture. It
was originally commissioned by the emperor Ashoka in the 3rd century BCE. Its nucleus was a simple hemispherical brick
structure built over the relics of the Buddha. .It is a perfect example of combination of solid figures. A big hemispherical dome
with a cuboidal structure mounted on it. (Take π= 22/7 )
i) Find the volume of the hemispherical dome if the height of the dome is 21 m.
ii) Find the cloth require covering the hemispherical dome if the radius of its base is 14m.
iii) The total surface area of the combined figure i.e. hemispherical dome with radius 14m and cubical shaped top
with dimensions 8m ×6m ×4m is
OR
Find the volume of the cuboidal shaped top with dimensions 8m ×6m ×4m.
2. Isha’s father brought an ice-cream brick, empty cones and scoop to pour the ice-cream into cones for all the family members.
Dimensions of the ice-cream brick are (30cm×25cm×10cm) and radius of hemi-spherical scoop is 3.5 cm. Also the radius and
height of cone are 3.5 cm and 15cm respectively. Based on above information, answer the following questions
i) What is the volume of hemispherical scoop?
ii) Find volume of the ice-cream cone.
iii) Find the minimum number of scoops required to fill one cone up to brim.
OR
Find the number of cones that can be filled up to brim using the whole brick.
3. Alok and his family went for a vacation to Manali. There they had a stay in tent for a night. Alok found that the tent in which
they stayed is in the form of a cone surmounted on a cylinder. The total height of the tent is 42m.diameter of the base is 42m
and height of the cylinder is 22m. . Based on above information, answer the following questions
ANSWER KEY
1. (b) 10 cm 2. (d) 462cm2 3. (b) 3 : 1 4. (c) Right circular 5. (d) 16 : 9
6. (d) 5 : 1 7. (a) 9 : 8 8. (b) 160 cm2 9. (a) 3 : 7 10. (b) 7 cm
11. (c) 20 : 27 12 .(d) 33.1% 13. (b) 2.5cm 14. (a) 38.5 kl 15. (a) 1.75 m
Assertion and Reason
1. (a) Assertion and Reason both are correct statements and Reason is the correct explanation of Assertion.
2. (c)Assertion is correct statement but Reason is wrong statement.
3. (d) Assertion is wrong statement but Reason is correct statement
4. (d) Assertion is wrong statement but Reason is correct statement
CASE STUDY
1. SANCHI STUP
i) 19404 CU. M
ii) 1232 sq. m
iii) 1392 sq. m or 192 cu. M
2. Ice cream
i) 539/6 cu. Cm
ii) 192.5 cu. Cm
iii) No. of scoops to fill a cone= 2 or approx. 39
3. Tent
i) 4818 sq. m
ii) 11
iii) Rs. 20476.50 Or 39732 cu. M and no. of person=21
4. Water drop
i) 2 mm
ii) 10.68 sq. mm
1
iii) 𝑟=
3 3
(4) or no. of drops = 35000
Chapter 13 (Statistics)
Mean:
The arithmetic mean of a given data is the sum of the values of all the observations divided by the total number of observations.
There are two different formulas for calculating the mean for ungrouped data and the mean for grouped data.
Type 1 (Mean of raw data)
Suppose we have n values in a set of data namely as x1, x2, x3, ………….xn, then the mean of the data is given by using the formula
Solution:
(No of di = xi - a fidi
Female Employee(C I) Departments fi ) Class Marks xi
5-15 1 10 -30 -30
15-25 2 20 -20 -40
25-35 4 30 -10 -40
35-45 4 40 0 0
45-55 7 50 10 70
55-65 11 60 20 220
65-75 6 70 30 180
Total ∑fi =35 ∑fidi = 360
Assumed mean = a = 40
Mean = a+ (∑fidi /∑fi) = 40+ (360/35) = 40+(72/7) = 40 + 10.28 = 50.28
Hence, the mean percentage of female employees is 50.28.
Median
Algorithm
Obtain the frequency distribution
Prepare the cumulative frequency column
n
Obtain n = (∑ fi ) and
2
n
See the cumulative frequency just greater than (nearer to) 2 and determine the corresponding class. This class is known
as median class
Obtain the values of the following from the frequency distribution table
l = lower limit of the median class
f = frequency of median class
h = width(size) of the median class
cf = cumulative frequency of the class preceding the median class
Substitute the values in the following formula
n/2 −c f
Median = 𝑙 + ( )h
f
Example: Find the median of the following data is
Marks obtained 0-10 10-20 20-30 30-40 40-50
No of Students 5 7 4 8 6
Solution:
Marks Cumulative
obtained No of students frequency
0-10 5 5
10-20 7 5+7=12
20-30 4 12+4=16
30-40 8 16+8=24
40-50 6 24+6=30
Total N=30
We have
Lower limit of median class l = 20
Cumulative frequency preceding the median class cf =12 Frequency of the median class f=4
Class size= difference of limits h = 10
15−12
Median = 20 +( )×10 =20 +30/4 = 20 + 7.5 = 27.5
4
Mode
COMPUTATION OF MODE FOR A CONTINOUS FREQUENCY DISTRIBUTION
Obtain the continuous frequency distribution
Determine the class of maximum frequency either by inspection or by grouping method
This class is called the modal class
Obtain the values of the following from the frequency distribution table
𝑙 = 𝑙𝑜𝑤𝑒𝑟 𝑙𝑖𝑚𝑖𝑡 𝑜𝑓 𝑡ℎ𝑒 𝑚𝑜𝑑𝑎𝑙 𝑐𝑙𝑎𝑠𝑠
𝑓1 = 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 𝑜𝑓 𝑚𝑜𝑑𝑎𝑙 𝑐𝑙𝑎𝑠𝑠
ℎ = 𝑤𝑖𝑑𝑡ℎ(𝑠𝑖𝑧𝑒) of the modal class
𝑓0 = 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 𝑜𝑓 𝑡ℎ𝑒 𝑐𝑙𝑎𝑠𝑠 𝑝𝑟𝑒𝑐𝑒𝑑𝑖𝑛𝑔 𝑡ℎ𝑒 𝑚𝑜𝑑𝑎𝑙 𝑐𝑙𝑎𝑠𝑠
𝑓2 = 𝑓𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 𝑜𝑓 𝑡ℎ𝑒 𝑐𝑙𝑎𝑠𝑠 𝑓𝑜𝑙𝑙𝑜𝑤𝑖𝑛𝑔 𝑡ℎ𝑒 𝑚𝑜𝑑𝑎𝑙 class
𝑓 −𝑓
Mode = 𝑙 + (2𝑓 −𝑓
1 0
)ℎ
1 −𝑓0 2
THE EMPIRICAL RELATIONSHIP BETWEEN THE THREE MEASURES OF CENTRAL TENDENCY
3 median = mode + 2 mean
EXAMPLE
The following data gives the information on the observed life times (in hours) of 150 electrical components. Find the mode
SOLUTION:
The class 60-80 have the maximum frequency as 50
Modal class is 60-80
So, l = 60, f0 = 35, f1 = 50, f2 = 40, h = 20
𝑓 −𝑓 50−35
Mode = 𝑙 + (2𝑓 −𝑓
1 0
)ℎ = 60 + ( ) × 20 = 72
1 −𝑓0 2 2×50−35−40
QUESTIONS
Type 1 MCQ
1. Find the class marks of classes 10-20 and 35-55:
(a) 10, 35 (b) 20, 55 (c) 15, 45 (d) 17.5, 45
2. If di = xi - 13, ∑fidi = 30 and ∑fi=120 , then mean is equal to:
(a) 13 (b) 12.75 (c) 13.25 (d) 14.25
3. The mean of first ten odd natural numbers is:
(a) 5 (b) 10 (c) 20 (d) 19
4. If the mean of x, x + 3, x + 6, x + 9 and x + 12 is 10, then x equals:
(a) 1 (b) 2 (c) 4 (d) 6
5. For a frequency distribution, mean, median and mode are connected by the relation:
(a) Mode = 3 Mean - 2 Median (b) Mode = 2 Median - 3 Mean
(c) Mode = 3 Median - 2 Mean (d) Mode = 3 Median + 2 Mean.
5𝑛
6. The mean of first n natural numbers is 9 then n is:
(a) 5 (b) 9 (c) 4 (d) 10
7. If Median of data 16,18, 20, 24-x, 20 + 2x, 28, 30, 32 is 24 then x is:
(a) 4 (b) 18 (c) 16 (d) 20
8. The Mean of five numbers is 15. If we include one more number, the mean of 6 numbers become 17. The included number is:
(a) 24 (b) 26 (c) 25 (d) 27
Frequency 8 16 36 34 6 100
14. Find the modal literacy rate of 40 cities:
Literacy rate 30-40 40-50 50-60 60-70 70-80 80-90
No of cities 6 7 10 6 8 3
15. Find the missing frequencies f1, f2 and f3 in the following frequency distribution, when it is given that f2 : f3 = 4 : 3, and mean =
50:
CI 0-20 20-40 40-60 60-80 80-100 TOTAL
Frequency 17 f1 f2 f3 19 120
16. The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is Rs. 18.
Find the missing frequency f:
Daily pocket allowance 11-13 13-15 15-17 17-19 19-21 21-23 23-25
No of children 7 6 9 13 f 5 4
17. A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a
student was absent:
No of days 0-6 6-10 10-14 14-20 20-28 28-38 38-40
No of students 11 10 7 4 4 3 1
18. If the median of the distribution given below is 28.5, find the values of x and y:
CI 0-10 10-20 20-30 30-40 40-50 50-60 TOTAL
FREQUENCY 5 X 20 15 Y 5 60
19. A life insurance agent found the following data for distribution of ages of 100 policy holders. Calculate the median age, if
policies are given only to persons having age 18 years onwards but less than 60 year:
Age (in years) Number of policy holders
Below 20 2
Below 25 6
Below 30 24
Below 35 45
Below 40 78
Below 45 89
Below 50 92
Below 55 98
Below 60 100
20. An agency has decided to install customized playground equipment’s at various colony parks. For that they decided to study
the age group of children playing in a park of the particular colony The classification of children according to their ages,
playing in a park is shown in the following table:
A survey is conducted for 56 families of a Colony A. The following table gives the weekly consumption of electricity of these families.
Weekly consumption (in units) 0-10 10-20 20-30 30-40 40-50 50-60
No. of families 16 11 19 6 4 0
i. Find the difference between upper limit of the modal class and lower limit of median class.
ii. Calculate mean of the data.
iii. Calculate the mode of this data.
Or
Calculate the cumulative frequency and also find the median group.
22. On a particular day, National Highway Authority of India (NHAI) checked the toll tax collection of a particular toll plaza in
Rajasthan. The following table shows the toll tax paid by drivers and the number of vehicles on that particular day.
Daily distance travelled (in km) 200-209 210-219 220-229 230-239 240-249
Number of buses 4 14 26 10 6
(i) Find the difference between upper limit of a class and lower limit of its succeeding class.
(ii) Find the median class.
(iii) The cumulative frequency of the class preceding the median class is :
Or
Find the median of distance travelled.
24. If mode of the following distribution is 55, then find the value of x.
Class 0-15 15-30 30-45 45-60 60-75 75-90
Frequency 10 7 x 15 10 12
25. Find mean and mode of the given data. Also find median using Empirical Formula.
Class 20-30 30-40 40-50 50-60 60-70
Frequency 25 40 42 33 10
ANSWER KEY:
1. C 2. C 3. B 4. C
2. 5. C 6. B 7. A 8. D
9. D 10. D 11. C 12. A
13. 27.22 14. 58.57 15. F1 = 28, F2 = 32, F3 = 24 16. 20
17. 12.48 19. 35.76
20. (i) 10-12 (ii) 10.6 (iii) 11
21. (i) 10 (ii) 19.8 (iii) 23.8
22. (i) 55 (ii) 50-60 (iii) 52.14
23. (i) 1 (ii) 219.5-229.5 (iii) 18 OR 224.6
24. X = 5
25. MODE = 42.22, MEAN = 31.3,
Chapter 14 (Probability)
1. The theoretical (classical) probability of an event E, written as P(E), is defined as
𝑁𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑜𝑢𝑡𝑐𝑜𝑚𝑒𝑠 𝑓𝑎𝑣𝑜𝑢𝑟𝑎𝑏𝑙𝑒 𝑡𝑜 𝐸
P(E) =
𝑇𝑜𝑡𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑝𝑜𝑠𝑠𝑖𝑏𝑙𝑒 𝑜𝑢𝑡𝑐𝑜𝑚𝑒𝑠 𝑡𝑜 𝐸
Where, we assume that the outcomes of the experiment are equally likely.
2. The probability of a sure event (or certain event) is 1.
3. The probability of an impossible event is 0.
4. The probability of an event E is P(E) such that 0 ≤ P(E) ≤1
5. An event having only one outcome is called an elementary event. The sum of the probabilities of all the elementary events of an
experiment is 1.
̅)=1
6. For any event E, P( E ) + P ( E
Where E stands for ‘not E'. E and ̅
̅ E are called complementary events.
7. Playing cards:
It consists of 52 cards which are divided into 4 suits of 13 cards each:
(i) Spade ♠ (Black colour) (iii) Club ♣ (Black colour)
(ii) Diamond ♦ (Red colour) (iv) Heart ♥ (Red colour)
Face cards: King, Queen, Jack
Questions:
1. Which of the following cannot be the probability of an event?
2
(A) 0.7 (B) 3 (C) - 1.5 (D) 15%
2. Out of one digit prime numbers, one number is selected at random. The probability of selecting an even number is:
1 1 4 2
(A) 2 (B) 4 (C) 9 (D) 5
3. When a die is thrown, the probability of getting an odd number less than3 is:
1 1 1
(A) 6 (B) 3 (C) 2 (D) 0
4. A card is drawn from a well shuffled pack of 52 playing cards. The event E is that the card drawn is not a face card. The number
of outcomes favourable to the event E is
(A) 51 (B) 40 (C) 36 (D) 12
5. In a family of 3 children, the probability of having at least one boy is:
7 1 5 3
(A) 8 (B) 8 (C) 8 (D) 4
6. The probability of a number selected at random from the numbers 1, 2, 3, .... 15 is a multiple of 4 is:
4 2 1 1
(A) 15 (B) 15 (C) 5 (D) 3
7. A bag contains 6 red and 5 blue balls. One ball is drawn at random. The probability that the ball is blue is:
2 5 5 6
(A) 11 (B) 6 (C) 11 (D) 11
8. Two dice, one blue and one grey, are thrown at the same time. Write down all the possible outcomes. What is the probability
that the sum of the two numbers appearing on the top of the dice is
(i) 8? (ii) 13? (iii) Less than or equal to 12?
9. 12 defective pens are accidentally mixed with 132 good ones. It is not possible to just look at a pen and tell whether or not it is
defective. One pen is taken out at random from this lot. Determine the probability that the pen taken out is a good one.
10. A box contains 90 discs which are numbered from 1 to 90. If one disc is drawn at random from the box, find the probability
that it bears (i) a two-digit number (ii) a perfect square number (iii) a number divisible by 5
11. A lot consists of 144 ball pens of which 20 are defective and the others are good. Nuri will buy a pen if it is good, but will not
buy if it is defective. The shopkeeper draws one pen at random and gives it to her. What is the probability that
(i) She will buy it? (ii) She will not buy it?
12. A letter of English alphabet is chosen at random. Determine the probability that the chosen letter is a consonant
13. A card is drawn from a well-shuffled deck of 52 playing cards. Then what is the probability that the card will not be a
diamond?
14. The probability of selecting a rotten apple randomly from a heap of 900 apples is 0.18. What is the number of rotten apples in
the heap?
15. Cards bearing numbers 2 to 21 are placed in a bag and mixed thoroughly. A card is taken out of the bag at random. What is the
probability that the number on the card taken out is an even number?
16. A card is drawn out from a well-shuffled deck of 52 cards. What is the probability of getting a red queen?
17. Two different dice are tossed together. Find the probability that (i) the number on each dice is odd, and (ii) the sum on the
numbers, appearing on the two dice, is 5.
18. Rahim tosses two different coins simultaneously. Find the probability of getting at least one tail.
19. A card is drawn at random from a well-shuffled pack of 52 cards. Find the probability that the card is neither a red card nor a
jack.
20. A box contains 100 red cards, 200 yellow cards and 50 blue cards. If a card is drawn at random from the box, then find the
probability that it will be :
(i) a blue card,
(ii) not a yellow card, and
(iii) neither yellow nor a blue card.
Answers:
1: C 2: C 3: A 4: B 5: A 6: C
7: C 8: (i) 5/36 (ii) 0 (iii) 1 9: 11/12
10 (i) 9/10 (ii) 1/10 (iii) 1/5 11: (i) 31/36 (ii) 5/36 12: 21/26 13: 3/4
14: 162 15: 1/2 16: 1/26 17: (i) 1/4 (ii) 1/9 18: 3/4
19: 6/13 20: (i) 1/7 (ii) 3/7 (iii) 2/7
Assertion and Reasoning Questions:
In the following questions, a statement of assertion (A) is followed by a statement of reason (R). Mark the correct choice as:
(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
1. Assertion (A): If a box contains 5 white, 2 red and 4 black marbles, then the probability of not drawing a white marble from the
5
box is 11.
Reason (R): P(E̅) = 1 – P(E), where E is any event.
1
2. Assertion (A): When two coins are tossed simultaneously then the probability of getting no tail is 4.
1
Reason (R): The probability of getting a head (i.e., no tail) in one toss of a coin is .
2
3. Assertion (A): If a die is thrown, the probability of getting a number less than 3 and greater than 2 is zero.
Reason (R): Probability of an impossible event is zero.
1
4. Assertion (A): In a simultaneously throw of a pair of dice, the probability of getting a doublet is 6.
Reason (R): Probability of an event may be negative.
5. Assertion (A): The probability of winning a game is 0.4, then the probability of losing it, is 0.6.
Reason (R): P( E ) + P(E̅) = 1.
Answers:
Q no. 1 2 3 4 5
Answer D B A C A
1
(i) If the probability of distributing milk chocolate is 3, then find the number of milk chocolate Rohit has. 1 mark
4
(ii) If the probability of distributing dark chocolate is 9 then find the number of dark chocolate Rohit has. 1 mark
(iii) Find the probability of distributing both milk and white chocolate. 2 marks
OR
Find the probability of distributing both white and dark chocolate.
1. Four friends are playing with cards. One of them hides all that 2’s, 5’s and Jacks from the deck of 52 cards and then shuffles
the remaining cards. Now, he tells to one of his friend to pick a card at random from the remaining cards.
3. Two friends A and B are playing a game. They roll a pair of fair dice one by one. The game starts with A.
(i) Now B rolls the dice, find the chances that he will get consecutive numbers. 1 marks
(ii) Now A rolls the dice again, find the chance that he gets more than 4 on each die. 1 marks
(iii) Now B rolls the dice again, find the chance that he gets even numbers on both dice. 2 marks
OR
Now B rolls the dice again, find the chance that he gets odd numbers on both dice.
Answers:
1. (i) 18 (ii) 24 (iii) 30 OR 36
2. (i) 1/10 (ii) 0 (iii) 1/5 OR 4/5
3. (i) 1/8 (ii) 3/8 (iii) 1 OR 1/2
4. (i) 5/18 (ii)1/9 (iii) 1/4 OR 1/4
………………THANK YOU……………