There were 9 more girls than boys in the school hall. Excluding 12 boys, the number of boys was
23 of the number of girls. When another 3 girls joined, what fraction of the students were girls in the end? Give your answer in its simplest form.
|
Girls |
Boys |
Comparing girls and boys at first |
9 more |
|
Before |
3 u |
2 u + 12 |
Change |
+ 3 |
|
After |
3 u + 3 |
2 u + 12 |
Number of girls at first was 9 more than the number of boys. If another 9 boys entered the school hall at first, the number of girls and boys at first would be the same.
3 u = 2 u + 12 + 9
3 u - 2 u = 12 + 9
1 u = 21
Total number of girls in the end
= 3 u + 3
= 3 x 21 + 3
= 63 + 3
= 66
Total number of students in the end
= 3 u + 3 + 2 u + 12
= 5 u + 15
= 5 x 21 + 15
= 120
Fraction of the students who were girls in the end
=
66120 =
1120 Answer(s):
1120