At a school, there were 50 girls from Club C and 20% more girls from Club D. Some girls from Club D left and the ratio of the number of girls from Club C to the number of girls from Club D became 5 : 3. How many girls from Club D left?
|
Club C |
Club D |
Before |
50 |
60 |
Change |
|
- ? |
After |
5 u |
3 u |
Number of girls from Club D at first in percent
= 100% + 20%
= 120%
Number of girls from Club D at first
= 120% x 50
=
120100 x 50
= 60
Number of girls in Club C remains unchanged.
5 u = 50
1 u = 50 ÷ 5 = 10
Number of girls from Club D in the end
= 3 u
= 3 x 10
= 30
Number of girls from Club D who left
= 60 - 30
= 30
Answer(s): 30