672 people went to a bird park.
37 were adults. Some children left halfway and the ratio of the number of adults to the number of children became 12 : 13. How many children left the bird park halfway?
| |
Adults |
Children |
Total |
| Before |
3x4 =
12 u |
4x4 =
16 u |
7x4 =
28 u |
| Change |
|
- ? |
|
| After |
12 u |
13 u |
|
Fraction of the people that were children at first
= 1 -
37 =
47 Number of adults remains unchanged. Make the number of adults the same. LCM of 3 and 12 is 12.
Total number of people at first = 28 u
28 u = 672
1 u = 672 ÷ 28 = 24
Number of children who left halfway
= 16 u - 13 u
= 3 u
= 3 x 24
= 72
Answer(s): 72
