There was an equal number of boys and girls at the school hall. After
37 of the boys and 31 girls left the school hall, there were 13 more boys than girls at the school hall. How many students were there at the school hall at first?
|
Boys |
Girls |
Before |
7 u |
7 u |
Change |
- 3 u |
- 31 |
After |
4 u |
7 u - 31 |
Number of boys in the end
= 7 u - 3 u
= 4 u
If another 13 girls entered the school hall, the number of boys and girls would be the same.
7 u - 31 + 13 = 4 u
7 u - 18 = 4 u
7 u - 4 u = 18
3 u = 18
1 u = 18 ÷ 3 = 6
Number of students in the school hall at first
= 14 u
= 14 x 6
= 84
Answer(s): 84