At a school, there were 15 girls from Club S and 20% more girls from Club T. Some girls from Club T left and the ratio of the number of girls from Club S to the number of girls from Club T became 5 : 4. How many girls from Club T left?
| |
Club S |
Club T |
| Before |
15 |
18 |
| Change |
|
- ? |
| After |
5 u |
4 u |
Number of girls from Club T at first in percent
= 100% + 20%
= 120%
Number of girls from Club T at first
= 120% x 15
=
120100 x 15
= 18
Number of girls in Club S remains unchanged.
5 u = 15
1 u = 15 ÷ 5 = 3
Number of girls from Club T in the end
= 4 u
= 4 x 3
= 12
Number of girls from Club T who left
= 18 - 12
= 6
Answer(s): 6
