320 people went to a bird park.
38 were children. Some adults left halfway and the ratio of the number of children to the number of adults became 12 : 17. How many adults left the bird park halfway?
|
Children |
Adults |
Total |
Before |
3x4 = 12 u |
5x4 = 20 u |
8x4 = 32 u |
Change |
|
- ? |
|
After |
12 u |
17 u |
|
Fraction of the people that were adults at first
= 1 -
38 =
58 Number of children remains unchanged. Make the number of children the same. LCM of 3 and 12 is 12.
Total number of people at first = 32 u
32 u = 320
1 u = 320 ÷ 32 = 10
Number of adults who left halfway
= 20 u - 17 u
= 3 u
= 3 x 10
= 30
Answer(s): 30