160 people went to a stadium.
34 were adults. Some children joined halfway and the ratio of the number of adults to the number of children became 12 : 7. How many children joined the stadium halfway?
|
Adults |
Children |
Total |
Before |
3x4 = 12 u |
1x4 = 4 u |
4x4 = 16 u |
Change |
|
+ ? |
|
After |
12 u |
7 u |
|
Fraction of the people that were children at first
= 1 -
34 =
14 Number of adults remains unchanged. Make the number of adults the same. LCM of 3 and 12 is 12.
Total number of people at first = 16 u
16 u = 160
1 u = 160 ÷ 16 = 10
Number of children who joined halfway
= 7 u - 4 u
= 3 u
= 3 x 10
= 30
Answer(s): 30