At a school, there were 30 boys from Club T and 30% less boys from Club U. Some boys joined Club U and the ratio of the number of boys from Club T to the number of boys from Club U became 6 : 5. How many boys joined Club U?
| |
Club T |
Club U |
| Before |
30 |
21 |
| Change |
|
+ ? |
| After |
6 u |
5 u |
Number of boys from Club U at first in percent
= 100% - 30%
= 70%
Number of boys from Club U at first
= 70% x 30
=
70100 x 30
= 21
Number of boys in Club T remains unchanged.
6 u = 30
1 u = 30 ÷ 6 = 5
Number of boys from Club U in the end
= 5 u
= 5 x 5
= 25
Number of boys joined Club U
= 25 - 21
= 4
Answer(s): 4
