At a school, there were 10 pupils from Club C and 20% more pupils from Club D. Some pupils from Club D left and the ratio of the number of pupils from Club C to the number of pupils from Club D became 5 : 2. How many pupils from Club D left?
|
Club C |
Club D |
Before |
10 |
12 |
Change |
|
- ? |
After |
5 u |
2 u |
Number of pupils from Club D at first in percent
= 100% + 20%
= 120%
Number of pupils from Club D at first
= 120% x 10
=
120100 x 10
= 12
Number of pupils in Club C remains unchanged.
5 u = 10
1 u = 10 ÷ 5 = 2
Number of pupils from Club D in the end
= 2 u
= 2 x 2
= 4
Number of pupils from Club D who left
= 12 - 4
= 8
Answer(s): 8