400 people went to a park.
25 were adults. Some children left halfway and the ratio of the number of adults to the number of children became 8 : 9. How many children left the park halfway?
|
Adults |
Children |
Total |
Before |
2x4 = 8 u |
3x4 = 12 u |
5x4 = 20 u |
Change |
|
- ? |
|
After |
8 u |
9 u |
|
Fraction of the people that were children at first
= 1 -
25 =
35 Number of adults remains unchanged. Make the number of adults the same. LCM of 2 and 8 is 8.
Total number of people at first = 20 u
20 u = 400
1 u = 400 ÷ 20 = 20
Number of children who left halfway
= 12 u - 9 u
= 3 u
= 3 x 20
= 60
Answer(s): 60