In February, the ratio of girls and boys in a school's Computer Club was 3 : 7. In March, 50 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 February. How many of the new members were boys?
|
Girls |
Boys |
Before |
3 u |
7 u |
Change |
+ 50 |
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 + 50
= 70
Total number of members in the end
= 4 p + 3 p
= 7 p
7 p = 70
1 p = 70 ÷ 7 = 10
Number of boys in the end
= 3 p
= 3 x 10
= 30
Number of boys at first
= 7 u
= 7 x 2
= 14
Number of new members who were boys
= 30 - 14
= 16
Answer(s): 16