There was an equal number of girls and boys at the school hall. After
47 of the girls and 42 boys left the school hall, there were 18 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 |
- 4 u |
- 42 |
After |
3 u |
7 u - 42 |
Number of girls in the end
= 7 u - 4 u
= 3 u
If another 18 boys entered the school hall, the number of girls and boys would be the same.
7 u - 42 + 18 = 3 u
7 u - 24 = 3 u
7 u - 3 u = 24
4 u = 24
1 u = 24 ÷ 4 = 6
Number of pupils in the school hall at first
= 14 u
= 14 x 6
= 84
Answer(s): 84