There were
13 as many children as adults on a bus. At the first bus stop, 18 children and 18 adults boarded the bus. There were then
56 as many children as adults. How many children were on the bus at first?
|
Children |
Adults |
Difference |
Before |
1x1 = 1 u |
3x1 = 3 u |
2x1 = 2 u |
Change |
+ 18 |
+ 18 |
|
After |
5x2 = 10 u |
6x2 = 12 u |
1x2 = 2 u |
Since equal number of children and adults boarded the bus, the difference in the number of children and adults at first and in the end remains the same. LCM of 2 and 1 is 2.
Number of children who boarded the bus
= 10 u - 1 u
= 9 u
9 u = 18
1 u = 18 ÷ 9 = 2
Number of children at first
= 1 u
= 1 x 2
= 2
Answer(s): 2