At first, there were 417 more girls than boys at the zoo. By 4 p.m., a total of 246 girls and boys left the zoo. There were as many girls as boys who left the zoo. In the end, there were 4 times as many girls as boys who remained behind. How many girls were at the zoo at first?
| |
Girls |
Boys |
Difference |
| Before |
4 u + 123 |
1 u + 123 |
417 |
| Change |
- 123 |
- 123 |
|
| After |
4 u |
1 u |
3 u |
Since there was the same number of boys and girls that left, the difference between the number of boys and girls remains unchanged.
3 u = 417
1 u = 417 ÷ 3 = 139
Number of girls in the end
= 4 u
= 4 x 139
= 556
Number of girls that left
= 246 ÷ 2
= 123
Number of girls at first
= 556 + 123
= 679
Answer(s): 679
