In February, the ratio of boys and girls in a school's Computer Club was 3 : 8. In March, 58 new members joined the club. As a result, the ratio of boys to girls in the club became 7 : 6. There were 9 boys in the Computer Club in February. How many of the new members were girls?
| |
Boys |
Girls |
| Before |
3 u |
8 u |
| Change |
+ 58 |
| After |
7 p |
6 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 + 58
= 91
Total number of members in the end
= 7 p + 6 p
= 13 p
13 p = 91
1 p = 91 ÷ 13 = 7
Number of girls in the end
= 6 p
= 6 x 7
= 42
Number of girls at first
= 8 u
= 8 x 3
= 24
Number of new members who were girls
= 42 - 24
= 18
Answer(s): 18
