210 people went to a museum.
27 were adults. Some children left halfway and the ratio of the number of adults to the number of children became 4 : 7. How many children left the museum halfway?
| |
Adults |
Children |
Total |
| Before |
2x2 =
4 u |
5x2 =
10 u |
7x2 =
14 u |
| Change |
|
- ? |
|
| After |
4 u |
7 u |
|
Fraction of the people that were children at first
= 1 -
27 =
57 Number of adults remains unchanged. Make the number of adults the same. LCM of 2 and 4 is 4.
Total number of people at first = 14 u
14 u = 210
1 u = 210 ÷ 14 = 15
Number of children who left halfway
= 10 u - 7 u
= 3 u
= 3 x 15
= 45
Answer(s): 45
