At a school, there were 30 children from Club B and 40% less children from Club C. Some children joined Club C and the ratio of the number of children from Club B to the number of children from Club C became 5 : 4. How many children joined Club C?
|
Club B |
Club C |
Before |
30 |
18 |
Change |
|
+ ? |
After |
5 u |
4 u |
Number of children from Club C at first in percent
= 100% - 40%
= 60%
Number of children from Club C at first
= 60% x 30
=
60100 x 30
= 18
Number of children in Club B remains unchanged.
5 u = 30
1 u = 30 ÷ 5 = 6
Number of children from Club C in the end
= 4 u
= 4 x 6
= 24
Number of children joined Club C
= 24 - 18
= 6
Answer(s): 6