At first, there were 416 more boys than girls at the bird park. By 1 p.m., a total of 250 boys and girls left the bird park. There were as many boys as girls who left the bird park. In the end, there were 5 times as many boys as girls who remained behind. How many boys were at the bird park at first?
|
Boys |
Girls |
Difference |
Before |
5 u + 125 |
1 u + 125 |
416 |
Change |
- 125 |
- 125 |
|
After |
5 u |
1 u |
4 u |
Since there was the same number of girls and boys that left, the difference between the number of girls and boys remains unchanged.
4 u = 416
1 u = 416 ÷ 4 = 104
Number of boys in the end
= 5 u
= 5 x 104
= 520
Number of boys that left
= 250 ÷ 2
= 125
Number of boys at first
= 520 + 125
= 645
Answer(s): 645