300 people went to a tourist attraction.
34 were children. Some adults joined halfway and the ratio of the number of children to the number of adults became 9 : 7. How many adults joined the tourist attraction halfway?
| |
Children |
Adults |
Total |
| Before |
3x3 =
9 u |
1x3 =
3 u |
4x3 =
12 u |
| Change |
|
+ ? |
|
| After |
9 u |
7 u |
|
Fraction of the people that were adults at first
= 1 -
34 =
14 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 = 12 u
12 u = 300
1 u = 300 ÷ 12 = 25
Number of adults who joined halfway
= 7 u - 3 u
= 4 u
= 4 x 25
= 100
Answer(s): 100
