At first, there were 440 more girls than boys at the zoo. By 4 p.m., a total of 250 girls and boys left the zoo. There were as many girls as boys who left the zoo. In the end, there were 3 times as many girls as boys who remained behind. How many girls were at the zoo at first?
|
Girls |
Boys |
Difference |
Before |
3 u + 125 |
1 u + 125 |
440 |
Change |
- 125 |
- 125 |
|
After |
3 u |
1 u |
2 u |
Since there was the same number of boys and girls that left, the difference between the number of boys and girls remains unchanged.
2 u = 440
1 u = 440 ÷ 2 = 220
Number of girls in the end
= 3 u
= 3 x 220
= 660
Number of girls that left
= 250 ÷ 2
= 125
Number of girls at first
= 660 + 125
= 785
Answer(s): 785