240 people went to a museum.
58 were adults. Some children joined halfway and the ratio of the number of adults to the number of children became 15 : 11. How many children joined the museum halfway?
|
Adults |
Children |
Total |
Before |
5x3 = 15 u |
3x3 = 9 u |
8x3 = 24 u |
Change |
|
+ ? |
|
After |
15 u |
11 u |
|
Fraction of the people that were children at first
= 1 -
58 =
38 Number of adults remains unchanged. Make the number of adults the same. LCM of 5 and 15 is 15.
Total number of people at first = 24 u
24 u = 240
1 u = 240 ÷ 24 = 10
Number of children who joined halfway
= 11 u - 9 u
= 2 u
= 2 x 10
= 20
Answer(s): 20