At a school, there were 50 boys from Club Y and 20% more boys from Club Z. Some boys from Club Z left and the ratio of the number of boys from Club Y to the number of boys from Club Z became 5 : 3. How many boys from Club Z left?
| |
Club Y |
Club Z |
| Before |
50 |
60 |
| Change |
|
- ? |
| After |
5 u |
3 u |
Number of boys from Club Z at first in percent
= 100% + 20%
= 120%
Number of boys from Club Z at first
= 120% x 50
=
120100 x 50
= 60
Number of boys in Club Y remains unchanged.
5 u = 50
1 u = 50 ÷ 5 = 10
Number of boys from Club Z in the end
= 3 u
= 3 x 10
= 30
Number of boys from Club Z who left
= 60 - 30
= 30
Answer(s): 30
