At a school, there were 25 boys from Club D and 40% less boys from Club E. Some boys joined Club E and the ratio of the number of boys from Club D to the number of boys from Club E became 5 : 4. How many boys joined Club E?
| |
Club D |
Club E |
| Before |
25 |
15 |
| Change |
|
+ ? |
| After |
5 u |
4 u |
Number of boys from Club E at first in percent
= 100% - 40%
= 60%
Number of boys from Club E at first
= 60% x 25
=
60100 x 25
= 15
Number of boys in Club D remains unchanged.
5 u = 25
1 u = 25 ÷ 5 = 5
Number of boys from Club E in the end
= 4 u
= 4 x 5
= 20
Number of boys joined Club E
= 20 - 15
= 5
Answer(s): 5
