Some passengers board a school bus.
At Bus Stop A,
13 of them alight
and 2 passengers board.
At Bus Stop B,
14 of the passengers alight
and 7 board.
If there are 13 passengers on the bus now,
how many passengers are on the bus at first?
|
Number of passengers |
Before |
3 u |
|
Change 1 At Bus Stop A |
- 1 u + 2 |
|
After 1 |
2 u + 2 |
4 p |
Change 2 At Bus Stop B |
|
- 1 p + 7 |
After 2 |
|
13 |
Working backwards.
Number of passengers in the end = 13
4 p - 1 p = 13 - 7
3 p = 6
1 p = 6 ÷ 3 = 2
4 p = 4 x 2
4 p = 8
2 u + 2 = 4 p
2 u + 2 = 8
2 u = 8 - 2
2 u = 6
1 u = 6 ÷ 2 = 3
Total number of passengers at first
= 3 u
= 3 x 3
= 9
Answer(s): 9