At a school, there were 15 children from Club Y and 20% more children from Club Z. Some children from Club Z left and the ratio of the number of children from Club Y to the number of children from Club Z became 5 : 4. How many children from Club Z left?
|
Club Y |
Club Z |
Before |
15 |
18 |
Change |
|
- ? |
After |
5 u |
4 u |
Number of children from Club Z at first in percent
= 100% + 20%
= 120%
Number of children from Club Z at first
= 120% x 15
=
120100 x 15
= 18
Number of children in Club Y remains unchanged.
5 u = 15
1 u = 15 ÷ 5 = 3
Number of children from Club Z in the end
= 4 u
= 4 x 3
= 12
Number of children from Club Z who left
= 18 - 12
= 6
Answer(s): 6