In September, the ratio of girls and boys in a school's Swimming Club was 3 : 5. In October, 93 new members joined the club. As a result, the ratio of girls to boys in the club became 7 : 6. There were 9 girls in the Swimming Club in September. How many of the new members were boys?
| |
Girls |
Boys |
| Before |
3 u |
5 u |
| Change |
+ 93 |
| After |
7 p |
6 p |
Number of girls at first = 3 u
3 u = 9
1 u = 9 ÷ 3 = 3
Total number of members at first
= 3 u + 5 u
= 8 u
= 8 x 3
= 24
Total number of members in the end
= 24 + 93
= 117
Total number of members in the end
= 7 p + 6 p
= 13 p
13 p = 117
1 p = 117 ÷ 13 = 9
Number of boys in the end
= 6 p
= 6 x 9
= 54
Number of boys at first
= 5 u
= 5 x 3
= 15
Number of new members who were boys
= 54 - 15
= 39
Answer(s): 39
