At a school, there were 10 children from Club R and 30% more children from Club S. Some children from Club S left and the ratio of the number of children from Club R to the number of children from Club S became 5 : 3. How many children from Club S left?
|
Club R |
Club S |
Before |
10 |
13 |
Change |
|
- ? |
After |
5 u |
3 u |
Number of children from Club S at first in percent
= 100% + 30%
= 130%
Number of children from Club S at first
= 130% x 10
=
130100 x 10
= 13
Number of children in Club R remains unchanged.
5 u = 10
1 u = 10 ÷ 5 = 2
Number of children from Club S in the end
= 3 u
= 3 x 2
= 6
Number of children from Club S who left
= 13 - 6
= 7
Answer(s): 7