At a school, there were 50 boys from Club E and 40% less boys from Club F. Some boys joined Club F and the ratio of the number of boys from Club E to the number of boys from Club F became 5 : 4. How many boys joined Club F?
|
Club E |
Club F |
Before |
50 |
30 |
Change |
|
+ ? |
After |
5 u |
4 u |
Number of boys from Club F at first in percent
= 100% - 40%
= 60%
Number of boys from Club F at first
= 60% x 50
=
60100 x 50
= 30
Number of boys in Club E remains unchanged.
5 u = 50
1 u = 50 ÷ 5 = 10
Number of boys from Club F in the end
= 4 u
= 4 x 10
= 40
Number of boys joined Club F
= 40 - 30
= 10
Answer(s): 10