648 people went to a zoo.
38 were children. Some adults joined halfway and the ratio of the number of children to the number of adults became 9 : 17. How many adults joined the zoo halfway?
|
Children |
Adults |
Total |
Before |
3x3 = 9 u |
5x3 = 15 u |
8x3 = 24 u |
Change |
|
+ ? |
|
After |
9 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 9 is 9.
Total number of people at first = 24 u
24 u = 648
1 u = 648 ÷ 24 = 27
Number of adults who joined halfway
= 17 u - 15 u
= 2 u
= 2 x 27
= 54
Answer(s): 54