At a school, there were 35 boys from Club L and 20% more boys from Club M. Some boys from Club M left and the ratio of the number of boys from Club L to the number of boys from Club M became 5 : 3. How many boys from Club M left?
| |
Club L |
Club M |
| Before |
35 |
42 |
| Change |
|
- ? |
| After |
5 u |
3 u |
Number of boys from Club M at first in percent
= 100% + 20%
= 120%
Number of boys from Club M at first
= 120% x 35
=
120100 x 35
= 42
Number of boys in Club L remains unchanged.
5 u = 35
1 u = 35 ÷ 5 = 7
Number of boys from Club M in the end
= 3 u
= 3 x 7
= 21
Number of boys from Club M who left
= 42 - 21
= 21
Answer(s): 21
