In January, the ratio of girls and boys in a school's Badminton Club was 3 : 5. In February, 49 new members joined the club. As a result, the ratio of girls to boys in the club became 5 : 4. There were 12 girls in the Badminton Club in January. How many of the new members were boys?
| |
Girls |
Boys |
| Before |
3 u |
5 u |
| Change |
+ 49 |
| After |
5 p |
4 p |
Number of girls at first = 3 u
3 u = 12
1 u = 12 ÷ 3 = 4
Total number of members at first
= 3 u + 5 u
= 8 u
= 8 x 4
= 32
Total number of members in the end
= 32 + 49
= 81
Total number of members in the end
= 5 p + 4 p
= 9 p
9 p = 81
1 p = 81 ÷ 9 = 9
Number of boys in the end
= 4 p
= 4 x 9
= 36
Number of boys at first
= 5 u
= 5 x 4
= 20
Number of new members who were boys
= 36 - 20
= 16
Answer(s): 16
