In April, the ratio of girls and boys in a school's Badminton Club was 3 : 8. In May, 77 new members joined the club. As a result, the ratio of girls to boys in the club became 6 : 5. There were 15 girls in the Badminton Club in April. How many of the new members were boys?
| |
Girls |
Boys |
| Before |
3 u |
8 u |
| Change |
+ 77 |
| After |
6 p |
5 p |
Number of girls at first = 3 u
3 u = 15
1 u = 15 ÷ 3 = 5
Total number of members at first
= 3 u + 8 u
= 11 u
= 11 x 5
= 55
Total number of members in the end
= 55 + 77
= 132
Total number of members in the end
= 6 p + 5 p
= 11 p
11 p = 132
1 p = 132 ÷ 11 = 12
Number of boys in the end
= 5 p
= 5 x 12
= 60
Number of boys at first
= 8 u
= 8 x 5
= 40
Number of new members who were boys
= 60 - 40
= 20
Answer(s): 20
