In September, the ratio of girls and boys in a school's Tennis Club was 3 : 7. In October, 29 new members joined the club. As a result, the ratio of girls to boys in the club became 4 : 3. There were 6 girls in the Tennis Club in September. How many of the new members were boys?
| |
Girls |
Boys |
| Before |
3 u |
7 u |
| Change |
+ 29 |
| After |
4 p |
3 p |
Number of girls at first = 3 u
3 u = 6
1 u = 6 ÷ 3 = 2
Total number of members at first
= 3 u + 7 u
= 10 u
= 10 x 2
= 20
Total number of members in the end
= 20 + 29
= 49
Total number of members in the end
= 4 p + 3 p
= 7 p
7 p = 49
1 p = 49 ÷ 7 = 7
Number of boys in the end
= 3 p
= 3 x 7
= 21
Number of boys at first
= 7 u
= 7 x 2
= 14
Number of new members who were boys
= 21 - 14
= 7
Answer(s): 7
