At a school, there were 35 boys from Club K and 20% more boys from Club L. Some boys from Club L left and the ratio of the number of boys from Club K to the number of boys from Club L became 5 : 4. How many boys from Club L left?
| |
Club K |
Club L |
| Before |
35 |
42 |
| Change |
|
- ? |
| After |
5 u |
4 u |
Number of boys from Club L at first in percent
= 100% + 20%
= 120%
Number of boys from Club L at first
= 120% x 35
=
120100 x 35
= 42
Number of boys in Club K remains unchanged.
5 u = 35
1 u = 35 ÷ 5 = 7
Number of boys from Club L in the end
= 4 u
= 4 x 7
= 28
Number of boys from Club L who left
= 42 - 28
= 14
Answer(s): 14
