At a school, there were 15 girls from Club A and 40% less girls from Club B. Some girls joined Club B and the ratio of the number of girls from Club A to the number of girls from Club B became 5 : 4. How many girls joined Club B?
| |
Club A |
Club B |
| Before |
15 |
9 |
| Change |
|
+ ? |
| After |
5 u |
4 u |
Number of girls from Club B at first in percent
= 100% - 40%
= 60%
Number of girls from Club B at first
= 60% x 15
=
60100 x 15
= 9
Number of girls in Club A remains unchanged.
5 u = 15
1 u = 15 ÷ 5 = 3
Number of girls from Club B in the end
= 4 u
= 4 x 3
= 12
Number of girls joined Club B
= 12 - 9
= 3
Answer(s): 3
