280 people went to a park.
35 were children. Some adults joined halfway and the ratio of the number of children to the number of adults became 12 : 11. How many adults joined the park halfway?
| |
Children |
Adults |
Total |
| Before |
3x4 =
12 u |
2x4 =
8 u |
5x4 =
20 u |
| Change |
|
+ ? |
|
| After |
12 u |
11 u |
|
Fraction of the people that were adults at first
= 1 -
35 =
25 Number of children remains unchanged. Make the number of children the same. LCM of 3 and 12 is 12.
Total number of people at first = 20 u
20 u = 280
1 u = 280 ÷ 20 = 14
Number of adults who joined halfway
= 11 u - 8 u
= 3 u
= 3 x 14
= 42
Answer(s): 42
