There was an equal number of boys and girls at the classroom. After
37 of the boys and 39 girls left the classroom, there were 24 more boys than girls at the classroom. How many pupils were there at the classroom at first?
| |
Boys |
Girls |
| Before |
7 u |
7 u |
| Change |
- 3 u |
- 39 |
| After |
4 u |
7 u - 39 |
Number of boys in the end
= 7 u - 3 u
= 4 u
If another 24 girls entered the classroom, the number of boys and girls would be the same.
7 u - 39 + 24 = 4 u
7 u - 15 = 4 u
7 u - 4 u = 15
3 u = 15
1 u = 15 ÷ 3 = 5
Number of pupils in the classroom at first
= 14 u
= 14 x 5
= 70
Answer(s): 70
