140 people went to a concert hall.
37 were children. Some adults left halfway and the ratio of the number of children to the number of adults became 6 : 5. How many adults left the concert hall halfway?
|
Children |
Adults |
Total |
Before |
3x2 = 6 u |
4x2 = 8 u |
7x2 = 14 u |
Change |
|
- ? |
|
After |
6 u |
5 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 6 is 6.
Total number of people at first = 14 u
14 u = 140
1 u = 140 ÷ 14 = 10
Number of adults who left halfway
= 8 u - 5 u
= 3 u
= 3 x 10
= 30
Answer(s): 30