Some adults board a school bus.
At Bus Stop A,
13 of them alight
and 4 adults board.
At Bus Stop B,
58 of the adults alight
and 9 board.
If there are 18 adults on the bus now,
how many adults are on the bus at first?
|
Number of adults |
Before |
3 u |
|
Change 1 At Bus Stop A |
- 1 u + 4 |
|
After 1 |
2 u + 4 |
8 p |
Change 2 At Bus Stop B |
|
- 5 p + 9 |
After 2 |
|
18 |
Working backwards.
Number of adults in the end = 18
8 p - 5 p = 18 - 9
3 p = 9
1 p = 9 ÷ 3 = 3
8 p = 8 x 3
8 p = 24
2 u + 4 = 8 p
2 u + 4 = 24
2 u = 24 - 4
2 u = 20
1 u = 20 ÷ 2 = 10
Total number of adults at first
= 3 u
= 3 x 10
= 30
Answer(s): 30