450 people went to a tourist attraction.
45 were adults. Some children joined halfway and the ratio of the number of adults to the number of children became 12 : 7. How many children joined the tourist attraction halfway?
|
Adults |
Children |
Total |
Before |
4x3 = 12 u |
1x3 = 3 u |
5x3 = 15 u |
Change |
|
+ ? |
|
After |
12 u |
7 u |
|
Fraction of the people that were children at first
= 1 -
45 =
15 Number of adults remains unchanged. Make the number of adults the same. LCM of 4 and 12 is 12.
Total number of people at first = 15 u
15 u = 450
1 u = 450 ÷ 15 = 30
Number of children who joined halfway
= 7 u - 3 u
= 4 u
= 4 x 30
= 120
Answer(s): 120