In May, the ratio of girls and boys in a school's Swimming Club was 3 : 7. In June, 58 new members joined the club. As a result, the ratio of girls to boys in the club became 6 : 5. There were 9 girls in the Swimming Club in May. How many of the new members were boys?
| |
Girls |
Boys |
| Before |
3 u |
7 u |
| Change |
+ 58 |
| After |
6 p |
5 p |
Number of girls at first = 3 u
3 u = 9
1 u = 9 ÷ 3 = 3
Total number of members at first
= 3 u + 7 u
= 10 u
= 10 x 3
= 30
Total number of members in the end
= 30 + 58
= 88
Total number of members in the end
= 6 p + 5 p
= 11 p
11 p = 88
1 p = 88 ÷ 11 = 8
Number of boys in the end
= 5 p
= 5 x 8
= 40
Number of boys at first
= 7 u
= 7 x 3
= 21
Number of new members who were boys
= 40 - 21
= 19
Answer(s): 19
