At first, there were 400 more boys than girls at the concert hall. By 3 p.m., a total of 236 boys and girls left the concert hall. There were as many boys as girls who left the concert hall. In the end, there were 6 times as many boys as girls who remained behind. How many boys were at the concert hall at first?
| |
Boys |
Girls |
Difference |
| Before |
6 u + 118 |
1 u + 118 |
400 |
| Change |
- 118 |
- 118 |
|
| After |
6 u |
1 u |
5 u |
Since there was the same number of girls and boys that left, the difference between the number of girls and boys remains unchanged.
5 u = 400
1 u = 400 ÷ 5 = 80
Number of boys in the end
= 6 u
= 6 x 80
= 480
Number of boys that left
= 236 ÷ 2
= 118
Number of boys at first
= 480 + 118
= 598
Answer(s): 598
