There was an equal number of girls and boys at the school hall. After
57 of the girls and 43 boys left the school hall, there were 13 more girls than boys at the school hall. How many pupils were there at the school hall at first?
| |
Girls |
Boys |
| Before |
7 u |
7 u |
| Change |
- 5 u |
- 43 |
| After |
2 u |
7 u - 43 |
Number of girls in the end
= 7 u - 5 u
= 2 u
If another 13 boys entered the school hall, the number of girls and boys would be the same.
7 u - 43 + 13 = 2 u
7 u - 30 = 2 u
7 u - 2 u = 30
5 u = 30
1 u = 30 ÷ 5 = 6
Number of pupils in the school hall at first
= 14 u
= 14 x 6
= 84
Answer(s): 84
