F5 C6 Permutation and Combination
F5 C6 Permutation and Combination
F5 C6 Permutation and Combination
PERMUTATIONS
1. Given the words PLACES. Find
a. The number of ways of arranging all the
Example Solution:
6! = 6.5.4.3.2.1
= 720
b. The number of ways of arranging four of the
is S
Example Solution:
The way to arrange alphabet S = 1
The way to arrange another 3 alphabets= 5 P 3
The number of arrangement = 1 x 5 P 3 = 60
2. How many four- digit numbers can be formed without repetitions from the digits 1, 2, 3, 4, 5, and 7 if
that number.
a) are even number
c) Consist of digit 5
B.
COMBINATIONS
Exercise B.1
1. How many ways to choose 5 books from 20
different books
Example solution:
and 6 women ?
20
C5
= 15504
Example Solution:
The numbers of ways = 7 C 3 x 6 C 3
= 700
2. A set of 20 students is made up of 10 students from each of two different year groups. Five
students are to be selected from the set, and the order of selection is unimportant. Find
A code is to be formed using those letters and digits. The code must consist of 3 letters followed by 2
digits. How many codes can be formed if no letter or digit is repeated in each code ?
2. A badminton team consist of 7 students. The team will be chosen from a group of 8 boys and 5 girls.
Find the number of team that can be formed such that each team consists of
i.
4 boys
ii.
[ 4 marks]
i.
ii.
Find the number of these arrangements in which the letters E and A are side by side .
2005, Paper 1 4. A debating team consists of 5 students. These 5 students are chosen from 4 monitors, 2
assistant monitors and 6 prefects. Calculate the number of different ways the team can be formed if
i.
There is no restriction
ii.
ASSESMENT
1. Find the number of the arrangement of all nine letters of word SELECTION in which
i.
ii.
Solution:
2. Four girls and three boys are to be seated in a row. Calculate the number of possible arrangements
i.
ii.
Solution:
3. Calculate the number of four digit even number can be formed from the digits 3, 4, 5, 6 and 9 without
repetitions.
Solution:
4. Three alphabets are chosen from the word WALID. Find the number of possible choice if
i.
ii.
Solution:
5. A bowling team consists of 8 person. The team will be chosen from a group of 7 boys and 6 girls. Find
the number of team that can be formed such that each team consists of
i.
3 boys
ii.
Solution:
ANSWER
Exercise A.1
1. c) 240 d) 240
2. a) 120 b) 240
Exercise B.1
2. a) 15504
c) 240
b) 10800
Problem solving
1. i) 40320
ii) 141120
ii) 3
d) 180