At a school, there were 30 boys from Club A and 40% less boys from Club B. Some boys joined Club B and the ratio of the number of boys from Club A to the number of boys from Club B became 5 : 4. How many boys joined Club B?
| |
Club A |
Club B |
| Before |
30 |
18 |
| Change |
|
+ ? |
| After |
5 u |
4 u |
Number of boys from Club B at first in percent
= 100% - 40%
= 60%
Number of boys from Club B at first
= 60% x 30
=
60100 x 30
= 18
Number of boys in Club A remains unchanged.
5 u = 30
1 u = 30 ÷ 5 = 6
Number of boys from Club B in the end
= 4 u
= 4 x 6
= 24
Number of boys joined Club B
= 24 - 18
= 6
Answer(s): 6
