456 people went to a concert hall.
38 were children. Some adults joined halfway and the ratio of the number of children to the number of adults became 9 : 19. How many adults joined the concert hall halfway?
| |
Children |
Adults |
Total |
| Before |
3x3 =
9 u |
5x3 =
15 u |
8x3 =
24 u |
| Change |
|
+ ? |
|
| After |
9 u |
19 u |
|
Fraction of the people that were adults at first
= 1 -
38 =
58 Number of children remains unchanged. Make the number of children the same. LCM of 3 and 9 is 9.
Total number of people at first = 24 u
24 u = 456
1 u = 456 ÷ 24 = 19
Number of adults who joined halfway
= 19 u - 15 u
= 4 u
= 4 x 19
= 76
Answer(s): 76
