At a school, there were 25 boys from Club C and 40% more boys from Club D. Some boys from Club D left and the ratio of the number of boys from Club C to the number of boys from Club D became 5 : 2. How many boys from Club D left?
| |
Club C |
Club D |
| Before |
25 |
35 |
| Change |
|
- ? |
| After |
5 u |
2 u |
Number of boys from Club D at first in percent
= 100% + 40%
= 140%
Number of boys from Club D at first
= 140% x 25
=
140100 x 25
= 35
Number of boys in Club C remains unchanged.
5 u = 25
1 u = 25 ÷ 5 = 5
Number of boys from Club D in the end
= 2 u
= 2 x 5
= 10
Number of boys from Club D who left
= 35 - 10
= 25
Answer(s): 25
