In July, the ratio of girls and boys in a school's Art Club was 5 : 8. In August, 78 new members joined the club. As a result, the ratio of girls to boys in the club became 7 : 6. There were 20 girls in the Art Club in July. How many of the new members were boys?
| |
Girls |
Boys |
| Before |
5 u |
8 u |
| Change |
+ 78 |
| After |
7 p |
6 p |
Number of girls at first = 5 u
5 u = 20
1 u = 20 ÷ 5 = 4
Total number of members at first
= 5 u + 8 u
= 13 u
= 13 x 4
= 52
Total number of members in the end
= 52 + 78
= 130
Total number of members in the end
= 7 p + 6 p
= 13 p
13 p = 130
1 p = 130 ÷ 13 = 10
Number of boys in the end
= 6 p
= 6 x 10
= 60
Number of boys at first
= 8 u
= 8 x 4
= 32
Number of new members who were boys
= 60 - 32
= 28
Answer(s): 28
