At first, there were 450 more boys than girls at the bird park. By 2 p.m., a total of 266 boys and girls left the bird park. There were as many boys as girls who left the bird park. In the end, there were 4 times as many boys as girls who remained behind. How many boys were at the bird park at first?
| |
Boys |
Girls |
Difference |
| Before |
4 u + 133 |
1 u + 133 |
450 |
| Change |
- 133 |
- 133 |
|
| After |
4 u |
1 u |
3 u |
Since there was the same number of girls and boys that left, the difference between the number of girls and boys remains unchanged.
3 u = 450
1 u = 450 ÷ 3 = 150
Number of boys in the end
= 4 u
= 4 x 150
= 600
Number of boys that left
= 266 ÷ 2
= 133
Number of boys at first
= 600 + 133
= 733
Answer(s): 733
