There were 9 more boys than girls in the tuck shop. Excluding 12 girls, the number of girls was
34 of the number of boys. When another 9 boys joined, what fraction of the pupils were boys in the end? Give your answer in its simplest form.
|
Boys |
Girls |
Comparing boys and girls at first |
9 more |
|
Before |
4 u |
3 u + 12 |
Change |
+ 9 |
|
After |
4 u + 9 |
3 u + 12 |
Number of boys at first was 9 more than the number of girls. If another 9 girls entered the tuck shop at first, the number of boys and girls at first would be the same.
4 u = 3 u + 12 + 9
4 u - 3 u = 12 + 9
1 u = 21
Total number of boys in the end
= 4 u + 9
= 4 x 21 + 9
= 84 + 9
= 93
Total number of pupils in the end
= 4 u + 9 + 3 u + 12
= 7 u + 21
= 7 x 21 + 21
= 168
Fraction of the pupils who were boys in the end
=
93168 =
3156 Answer(s):
3156