There were 8 more boys than girls in the auditorium. Excluding 12 girls, the number of girls was
45 of the number of boys. When another 12 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 |
8 more |
|
Before |
5 u |
4 u + 12 |
Change |
+ 12 |
|
After |
5 u + 12 |
4 u + 12 |
Number of boys at first was 8 more than the number of girls. If another 8 girls entered the auditorium at first, the number of boys and girls at first would be the same.
5 u = 4 u + 12 + 8
5 u - 4 u = 12 + 8
1 u = 20
Total number of boys in the end
= 5 u + 12
= 5 x 20 + 12
= 100 + 12
= 112
Total number of pupils in the end
= 5 u + 12 + 4 u + 12
= 9 u + 24
= 9 x 20 + 24
= 204
Fraction of the pupils who were boys in the end
=
112204 =
2851 Answer(s):
2851