There was an equal number of boys and girls at the music room. After
37 of the boys and 37 girls left the music room, there were 13 more boys than girls at the music room. How many pupils were there at the music room at first?
| |
Boys |
Girls |
| Before |
7 u |
7 u |
| Change |
- 3 u |
- 37 |
| After |
4 u |
7 u - 37 |
Number of boys in the end
= 7 u - 3 u
= 4 u
If another 13 girls entered the music room, the number of boys and girls would be the same.
7 u - 37 + 13 = 4 u
7 u - 24 = 4 u
7 u - 4 u = 24
3 u = 24
1 u = 24 ÷ 3 = 8
Number of pupils in the music room at first
= 14 u
= 14 x 8
= 112
Answer(s): 112
