There were 7 more boys than girls in the auditorium. Excluding 7 girls, the number of girls was
23 of the number of boys. When another 3 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 |
7 more |
|
| Before |
3 u |
2 u + 7 |
| Change |
+ 3 |
|
| After |
3 u + 3 |
2 u + 7 |
Number of boys at first was 7 more than the number of girls. If another 7 girls entered the auditorium at first, the number of boys and girls at first would be the same.
3 u = 2 u + 7 + 7
3 u - 2 u = 7 + 7
1 u = 14
Total number of boys in the end
= 3 u + 3
= 3 x 14 + 3
= 42 + 3
= 45
Total number of pupils in the end
= 3 u + 3 + 2 u + 7
= 5 u + 10
= 5 x 14 + 10
= 80
Fraction of the pupils who were boys in the end
=
4580 =
916 Answer(s):
916 
