There was an equal number of boys and girls at the gymnasium. After
25 of the boys and 41 girls left the gymnasium, there were 13 more boys than girls at the gymnasium. How many pupils were there at the gymnasium at first?
| |
Boys |
Girls |
| Before |
5 u |
5 u |
| Change |
- 2 u |
- 41 |
| After |
3 u |
5 u - 41 |
Number of boys in the end
= 5 u - 2 u
= 3 u
If another 13 girls entered the gymnasium, the number of boys and girls would be the same.
5 u - 41 + 13 = 3 u
5 u - 28 = 3 u
5 u - 3 u = 28
2 u = 28
1 u = 28 ÷ 2 = 14
Number of pupils in the gymnasium at first
= 10 u
= 10 x 14
= 140
Answer(s): 140
