There were 3 more boys than girls in the computer lab. Excluding 3 girls, the number of girls was
23 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 |
3 more |
|
Before |
3 u |
2 u + 3 |
Change |
+ 9 |
|
After |
3 u + 9 |
2 u + 3 |
Number of boys at first was 3 more than the number of girls. If another 3 girls entered the computer lab at first, the number of boys and girls at first would be the same.
3 u = 2 u + 3 + 3
3 u - 2 u = 3 + 3
1 u = 6
Total number of boys in the end
= 3 u + 9
= 3 x 6 + 9
= 18 + 9
= 27
Total number of pupils in the end
= 3 u + 9 + 2 u + 3
= 5 u + 12
= 5 x 6 + 12
= 42
Fraction of the pupils who were boys in the end
=
2742 =
914 Answer(s):
914