In April, the ratio of boys and girls in a school's Dance Club was 3 : 8. In May, 39 new members joined the club. As a result, the ratio of boys to girls in the club became 5 : 4. There were 9 boys in the Dance Club in April. How many of the new members were girls?
| |
Boys |
Girls |
| Before |
3 u |
8 u |
| Change |
+ 39 |
| After |
5 p |
4 p |
Number of boys at first = 3 u
3 u = 9
1 u = 9 ÷ 3 = 3
Total number of members at first
= 3 u + 8 u
= 11 u
= 11 x 3
= 33
Total number of members in the end
= 33 + 39
= 72
Total number of members in the end
= 5 p + 4 p
= 9 p
9 p = 72
1 p = 72 ÷ 9 = 8
Number of girls in the end
= 4 p
= 4 x 8
= 32
Number of girls at first
= 8 u
= 8 x 3
= 24
Number of new members who were girls
= 32 - 24
= 8
Answer(s): 8
