644 people went to a zoo.
27 were children. Some adults joined halfway and the ratio of the number of children to the number of adults became 8 : 23. How many adults joined the zoo halfway?
| |
Children |
Adults |
Total |
| Before |
2x4 =
8 u |
5x4 =
20 u |
7x4 =
28 u |
| Change |
|
+ ? |
|
| After |
8 u |
23 u |
|
Fraction of the people that were adults at first
= 1 -
27 =
57 Number of children remains unchanged. Make the number of children the same. LCM of 2 and 8 is 8.
Total number of people at first = 28 u
28 u = 644
1 u = 644 ÷ 28 = 23
Number of adults who joined halfway
= 23 u - 20 u
= 3 u
= 3 x 23
= 69
Answer(s): 69
