320 people went to a concert hall.
45 were children. Some adults joined halfway and the ratio of the number of children to the number of adults became 16 : 7. How many adults joined the concert hall halfway?
| |
Children |
Adults |
Total |
| Before |
4x4 =
16 u |
1x4 =
4 u |
5x4 =
20 u |
| Change |
|
+ ? |
|
| After |
16 u |
7 u |
|
Fraction of the people that were adults at first
= 1 -
45 =
15 Number of children remains unchanged. Make the number of children the same. LCM of 4 and 16 is 16.
Total number of people at first = 20 u
20 u = 320
1 u = 320 ÷ 20 = 16
Number of adults who joined halfway
= 7 u - 4 u
= 3 u
= 3 x 16
= 48
Answer(s): 48
