Some adults board a school bus.
At Bus Stop A,
25 of them alight
and 7 adults board.
At Bus Stop B,
57 of the adults alight
and 7 board.
If there are 15 adults on the bus now,
how many adults are on the bus at first?
|
Number of adults |
Before |
5 u |
|
Change 1 At Bus Stop A |
- 2 u + 7 |
|
After 1 |
3 u + 7 |
7 p |
Change 2 At Bus Stop B |
|
- 5 p + 7 |
After 2 |
|
15 |
Working backwards.
Number of adults in the end = 15
7 p - 5 p = 15 - 7
2 p = 8
1 p = 8 ÷ 2 = 4
7 p = 7 x 4
7 p = 28
3 u + 7 = 7 p
3 u + 7 = 28
3 u = 28 - 7
3 u = 21
1 u = 21 ÷ 3 = 7
Total number of adults at first
= 5 u
= 5 x 7
= 35
Answer(s): 35