At a school, there were 50 boys from Club H and 30% less boys from Club J. Some boys joined Club J and the ratio of the number of boys from Club H to the number of boys from Club J became 5 : 4. How many boys joined Club J?
| |
Club H |
Club J |
| Before |
50 |
35 |
| Change |
|
+ ? |
| After |
5 u |
4 u |
Number of boys from Club J at first in percent
= 100% - 30%
= 70%
Number of boys from Club J at first
= 70% x 50
=
70100 x 50
= 35
Number of boys in Club H remains unchanged.
5 u = 50
1 u = 50 ÷ 5 = 10
Number of boys from Club J in the end
= 4 u
= 4 x 10
= 40
Number of boys joined Club J
= 40 - 35
= 5
Answer(s): 5
