At a school, there were 20 pupils from Club B and 25% more pupils from Club C. Some pupils from Club C left and the ratio of the number of pupils from Club B to the number of pupils from Club C became 5 : 2. How many pupils from Club C left?
| |
Club B |
Club C |
| Before |
20 |
25 |
| Change |
|
- ? |
| After |
5 u |
2 u |
Number of pupils from Club C at first in percent
= 100% + 25%
= 125%
Number of pupils from Club C at first
= 125% x 20
=
125100 x 20
= 25
Number of pupils in Club B remains unchanged.
5 u = 20
1 u = 20 ÷ 5 = 4
Number of pupils from Club C in the end
= 2 u
= 2 x 4
= 8
Number of pupils from Club C who left
= 25 - 8
= 17
Answer(s): 17
