There was an equal number of boys and girls at the music room. After
59 of the boys and 30 girls left the music room, there were 20 more boys than girls at the music room. How many students were there at the music room at first?
| |
Boys |
Girls |
| Before |
9 u |
9 u |
| Change |
- 5 u |
- 30 |
| After |
4 u |
9 u - 30 |
Number of boys in the end
= 9 u - 5 u
= 4 u
If another 20 girls entered the music room, the number of boys and girls would be the same.
9 u - 30 + 20 = 4 u
9 u - 10 = 4 u
9 u - 4 u = 10
5 u = 10
1 u = 10 ÷ 5 = 2
Number of students in the music room at first
= 18 u
= 18 x 2
= 36
Answer(s): 36
