140 people went to a concert hall.
25 were children. Some adults left halfway and the ratio of the number of children to the number of adults became 4 : 3. How many adults left the concert hall halfway?
| |
Children |
Adults |
Total |
| Before |
2x2 =
4 u |
3x2 =
6 u |
5x2 =
10 u |
| Change |
|
- ? |
|
| After |
4 u |
3 u |
|
Fraction of the people that were adults at first
= 1 -
25 =
35 Number of children remains unchanged. Make the number of children the same. LCM of 2 and 4 is 4.
Total number of people at first = 10 u
10 u = 140
1 u = 140 ÷ 10 = 14
Number of adults who left halfway
= 6 u - 3 u
= 3 u
= 3 x 14
= 42
Answer(s): 42
