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