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MMW - 12.4.19 Activity - Polya - A2 - Mirasol

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MATHEMATICS IN THE MODERN WORLD – A2

APPLICATION OF POLYA’S STRATEGY


1. The GSM basketball team won three out of their last six games. In how many different orders
could they have attained three wins and three losses in six games?
a. Understand the Problem (Analysis)
GSM Team
Wins – 3 | Loses – 3
Number of Games: 6
b. Devise a Plan (Planning)
nCr = n!/(n-r)!r!
Let:
n = Number of games
r = the number of wins or loses which are 6 and 3 respectively.

c. Carry out the Plan (Implementation)


6!
6C3 =
( 6−3 ) ! 3 !
6C3 = 20
d. Look back (Reflection)
720 number of games
= 20 ✔
( 6−3 ) 3 !

2. Leonardo da Vinci was a famous artist during renaissance period. He wrote in his notebook that
“from the top to the bottom of the chin is the sixth part of the face, and it is fifty-fourth part of
the man.” Suppose the distance from top to bottom of the chin is 1.2 inches. Using Leonardo da
Vinci’s measurement, find the height of the person.
a. Understand the Problem (Analysis)
Top to Bottom of the chin > 6th part of his face > 54th part of his total height
b. Device a Plan
1 d
=
x h
Let:
x = 54th of the man’s total height
d = 1.2 the distance from the top to bottom of the chin
h = height of the man
c. Carry out the Plan
1 1.2
MIRASOL, ELIZA KATE B.

=
54 h
h=54 x 1.2
h = 64. 8
d. Look Back
1 1.2
=
54 64.8
64.8=64.8

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MATHEMATICS IN THE MODERN WORLD – A2

3. An agency charged P 15 000 for a 3-day and 2-night tour in Macau and P 20 000 for the same
tour with a side trip to Hongkong. Ten persons joined the trip, which enable them to collect P
170 000. How many tourists made a side trip to Hongkong?
a. Understand the Problem
P 15, 000 – if same tour
P 20, 000 – if same tour but with a side trip to Hong Kong
P 170, 000 – collected money of the 10 persons who joined the trip
b. Devise a Plan
Let:
y = the number of tourists who made a side trip to Hong Kong
10 = number of people who joined the trip
10 – y = number of tourists with the same tour but without a side trip to Hong Kong
(Same tour with a side trip to Hong Kong) y + (same tour) (10 – y) = collected money
c. Carry out the Plan
20, 000y + 15,000 (10 – y) = 170, 000
20, 000y + 15, 000 – 15, 000y = 170, 000
5, 000y = 20, 000
y=4
d. Look Back
Tourists that joined the Tourists who did not joined the
side Trip side trip
Tourist 1 = 20, 000 Tourist 5 = 15, 000
Tourist 2 = 20, 000 Tourist 6 = 15, 000
Tourist 3 = 20, 000 Tourist 7 = 15, 000
Tourist 4 = 20, 000 Tourist 8 = 15, 000
Tourist 9 = 15, 000
Tourist 10 = 15, 000

Total 1 = 80, 000 Total 2 = 90, 000

Grand total = Total 1 + Total 2


= 80, 000 + 90, 000
= 170, 000
 Therefore, Collected money ( 170, 000) is equal to the total money from the tourists who joined
MIRASOL, ELIZA KATE B.

the side trip and the tourist who did not.


 There are only 4 tourists who joined the tour with a side trip in Hong Kong.

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MATHEMATICS IN THE MODERN WORLD – A2

Continuation from book - Page 105


1. In the complex number system, i 1=i; i 2=−1 ; i 3=−i ;i 4=1 ; i5 =i, … Find i 173.

a. Understand the problem


To find i 173 with the given the complex number system.
b. Devise a Plan

Exponent of i Equivalent
1 i
2 -1
3 −i
4 1
5 i
6 -1

Based on the table, there are values repeating after a period of 4. Using this, we can
divide 173 by 4, then compare the remainder to the table.

c. Carry Out the Plan


173
=43 with remainder of 1. This means that i 173 =i1 =i
4

d. Look Back
By using modulo operations,
173 mod 4 = 1 mod 4 ✔
∴ the answer is correct MIRASOL, ELIZA KATE B.

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MATHEMATICS IN THE MODERN WORLD – A2

e. Find the last digit of the sum: 32018 + 4 2018

a. Understand the Problem

Find the last digit of the sum of two numbers raised by an exponent

b. Devise a Plan

n Last Digit of 3n Last Digit of 4 n


1 3 4
2 9 6
3 7 4
4 1 6
5 3 4
With accordance to the table, there is a pattern that can be observed. The last
digit of 3n repeats after a period of 4. However, the last digit of 4 n repeats after a
period of 2. With this, we divide the exponent by 4 and 2, the compare them to the
table of 3n and 4 n respectively.

c. Carry Out the Plan

2018
=504 remainder of 2. This means that 32018 =32=9.
4

2018
=1009. There is no remainder, then the exponent is equal to the period for 4 n.
2
This means that 4 2018 =4 2=16 . Thus, the last digit is 6.
Finding the sum of the two, 9 + 6 = 15
MIRASOL, ELIZA KATE B.

d. Look Back
Using Modulo operations,
2018 mod 4 = 2 mod 4
2018 mod 2 = 0 mod 2 = 2 mod 2 ✔
∴ the answer is correct.

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MATHEMATICS IN THE MODERN WORLD – A2

e. Yan was born exactly 78 days before Dong was born. If Dong was born on a Monday,
what day was Yan born?

a. Understand the Problem


Yan| x= 78 days y=? Dong |x=? y=Monday

b. Devise a Plan

Considered that today is Monday, then exactly 7 days ago is also a Monday knowing that
a week has 7 days. Through this, we can find the nearest multiple of 7 from 78 and working
backwards from there can be applied to reach the exact day that we are trying to find.
c. Carry Out the Plan

Days from Dong’s Birth Day


77 Monday
78 Sunday
79 Saturday
80 Friday
81 Thursday
82 Wednesday
83 Tuesday
Based on the table, 78 days from when Dong was born is a Sunday. Therefore,
Yan was born on a Sunday.

d. Look Back
MIRASOL, ELIZA KATE B.

It would be always a Sunday, 78 days before a Monday. For example, if today is


June 4, which is a Monday, then 78 days ago was March 18, which was a
Sunday. Therefore, the answer is correct. ✔

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