In July, the ratio of girls and boys in a school's Badminton Club was 3 : 7. In August, 59 new members joined the club. As a result, the ratio of girls to boys in the club became 6 : 5. There were 12 girls in the Badminton Club in July. How many of the new members were boys?
| |
Girls |
Boys |
| Before |
3 u |
7 u |
| Change |
+ 59 |
| After |
6 p |
5 p |
Number of girls at first = 3 u
3 u = 12
1 u = 12 ÷ 3 = 4
Total number of members at first
= 3 u + 7 u
= 10 u
= 10 x 4
= 40
Total number of members in the end
= 40 + 59
= 99
Total number of members in the end
= 6 p + 5 p
= 11 p
11 p = 99
1 p = 99 ÷ 11 = 9
Number of boys in the end
= 5 p
= 5 x 9
= 45
Number of boys at first
= 7 u
= 7 x 4
= 28
Number of new members who were boys
= 45 - 28
= 17
Answer(s): 17
