312 people went to a museum.
38 were children. Some adults left halfway and the ratio of the number of children to the number of adults became 9 : 13. How many adults left the museum halfway?
|
Children |
Adults |
Total |
Before |
3x3 = 9 u |
5x3 = 15 u |
8x3 = 24 u |
Change |
|
- ? |
|
After |
9 u |
13 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 = 312
1 u = 312 ÷ 24 = 13
Number of adults who left halfway
= 15 u - 13 u
= 2 u
= 2 x 13
= 26
Answer(s): 26