220 people went to a safari park.
25 were children. Some adults joined halfway and the ratio of the number of children to the number of adults became 4 : 9. How many adults joined the safari park halfway?
|
Children |
Adults |
Total |
Before |
2x2 = 4 u |
3x2 = 6 u |
5x2 = 10 u |
Change |
|
+ ? |
|
After |
4 u |
9 u |
|
Fraction of the people that were adults at first
= 1 -
25 =
35 Number of children remains unchanged. Make the number of children the same. LCM of 2 and 4 is 4.
Total number of people at first = 10 u
10 u = 220
1 u = 220 ÷ 10 = 22
Number of adults who joined halfway
= 9 u - 6 u
= 3 u
= 3 x 22
= 66
Answer(s): 66