There were 3 more boys than girls in the computer lab. Excluding 4 girls, the number of girls was
45 of the number of boys. When another 7 boys joined, what fraction of the students were boys in the end? Give your answer in its simplest form.
|
Boys |
Girls |
Comparing boys and girls at first |
3 more |
|
Before |
5 u |
4 u + 4 |
Change |
+ 7 |
|
After |
5 u + 7 |
4 u + 4 |
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.
5 u = 4 u + 4 + 3
5 u - 4 u = 4 + 3
1 u = 7
Total number of boys in the end
= 5 u + 7
= 5 x 7 + 7
= 35 + 7
= 42
Total number of students in the end
= 5 u + 7 + 4 u + 4
= 9 u + 11
= 9 x 7 + 11
= 74
Fraction of the students who were boys in the end
=
4274 =
2137 Answer(s):
2137