In January, the ratio of girls and boys in a school's Computer Club was 3 : 8. In February, 20 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 Computer Club in January. How many of the new members were boys?
| |
Girls |
Boys |
| Before |
3 u |
8 u |
| Change |
+ 20 |
| 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 + 8 u
= 11 u
= 11 x 2
= 22
Total number of members in the end
= 22 + 20
= 42
Total number of members in the end
= 4 p + 3 p
= 7 p
7 p = 42
1 p = 42 ÷ 7 = 6
Number of boys in the end
= 3 p
= 3 x 6
= 18
Number of boys at first
= 8 u
= 8 x 2
= 16
Number of new members who were boys
= 18 - 16
= 2
Answer(s): 2
