In October, the ratio of boys and girls in a school's Chess Club was 3 : 7. In November, 84 new members joined the club. As a result, the ratio of boys to girls in the club became 7 : 6. There were 6 boys in the Chess Club in October. How many of the new members were girls?
| |
Boys |
Girls |
| Before |
3 u |
7 u |
| Change |
+ 84 |
| After |
7 p |
6 p |
Number of boys 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 + 84
= 104
Total number of members in the end
= 7 p + 6 p
= 13 p
13 p = 104
1 p = 104 ÷ 13 = 8
Number of girls in the end
= 6 p
= 6 x 8
= 48
Number of girls at first
= 7 u
= 7 x 2
= 14
Number of new members who were girls
= 48 - 14
= 34
Answer(s): 34
