At a school, there were 10 pupils from Club X and 10% more pupils from Club Y. Some pupils from Club Y left and the ratio of the number of pupils from Club X to the number of pupils from Club Y became 5 : 4. How many pupils from Club Y left?
| |
Club X |
Club Y |
| Before |
10 |
11 |
| Change |
|
- ? |
| After |
5 u |
4 u |
Number of pupils from Club Y at first in percent
= 100% + 10%
= 110%
Number of pupils from Club Y at first
= 110% x 10
=
110100 x 10
= 11
Number of pupils in Club X remains unchanged.
5 u = 10
1 u = 10 ÷ 5 = 2
Number of pupils from Club Y in the end
= 4 u
= 4 x 2
= 8
Number of pupils from Club Y who left
= 11 - 8
= 3
Answer(s): 3
