224 people went to a concert hall.
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 concert hall 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 = 224
1 u = 224 ÷ 16 = 14
Number of children who joined halfway
= 7 u - 4 u
= 3 u
= 3 x 14
= 42
Answer(s): 42
