294 people went to a concert hall.
57 were children. Some adults joined halfway and the ratio of the number of children to the number of adults became 10 : 7. How many adults joined the concert hall halfway?
| |
Children |
Adults |
Total |
| Before |
5x2 =
10 u |
2x2 =
4 u |
7x2 =
14 u |
| Change |
|
+ ? |
|
| After |
10 u |
7 u |
|
Fraction of the people that were adults at first
= 1 -
57 =
27 Number of children remains unchanged. Make the number of children the same. LCM of 5 and 10 is 10.
Total number of people at first = 14 u
14 u = 294
1 u = 294 ÷ 14 = 21
Number of adults who joined halfway
= 7 u - 4 u
= 3 u
= 3 x 21
= 63
Answer(s): 63
