At first, there were 410 more boys than girls at the safari park. By 4 p.m., a total of 274 boys and girls left the safari park. There were as many boys as girls who left the safari park. In the end, there were 3 times as many boys as girls who remained behind. How many boys were at the safari park at first?
| |
Boys |
Girls |
Difference |
| Before |
3 u + 137 |
1 u + 137 |
410 |
| Change |
- 137 |
- 137 |
|
| After |
3 u |
1 u |
2 u |
Since there was the same number of girls and boys that left, the difference between the number of girls and boys remains unchanged.
2 u = 410
1 u = 410 ÷ 2 = 205
Number of boys in the end
= 3 u
= 3 x 205
= 615
Number of boys that left
= 274 ÷ 2
= 137
Number of boys at first
= 615 + 137
= 752
Answer(s): 752
