392 people went to a theme park.
57 were children. Some adults joined halfway and the ratio of the number of children to the number of adults became 20 : 11. How many adults joined the theme park halfway?
| |
Children |
Adults |
Total |
| Before |
5x4 =
20 u |
2x4 =
8 u |
7x4 =
28 u |
| Change |
|
+ ? |
|
| After |
20 u |
11 u |
|
Fraction of the people that were adults at first
= 1 -
57 =
27 Number of children remains unchanged. Make the number of children the same. LCM of 5 and 20 is 20.
Total number of people at first = 28 u
28 u = 392
1 u = 392 ÷ 28 = 14
Number of adults who joined halfway
= 11 u - 8 u
= 3 u
= 3 x 14
= 42
Answer(s): 42
