378 people went to a stadium.
37 were children. Some adults joined halfway and the ratio of the number of children to the number of adults became 9 : 16. How many adults joined the stadium halfway?
| |
Children |
Adults |
Total |
| Before |
3x3 =
9 u |
4x3 =
12 u |
7x3 =
21 u |
| Change |
|
+ ? |
|
| After |
9 u |
16 u |
|
Fraction of the people that were adults at first
= 1 -
37 =
47 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 = 21 u
21 u = 378
1 u = 378 ÷ 21 = 18
Number of adults who joined halfway
= 16 u - 12 u
= 4 u
= 4 x 18
= 72
Answer(s): 72
