Some passengers board a school bus.
At Bus Stop A,
13 of them alight
and 4 passengers board.
At Bus Stop B,
49 of the passengers alight
and 2 board.
If there are 12 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 + 4 |
|
After 1 |
2 u + 4 |
9 p |
Change 2 At Bus Stop B |
|
- 4 p + 2 |
After 2 |
|
12 |
Working backwards.
Number of passengers in the end = 12
9 p - 4 p = 12 - 2
5 p = 10
1 p = 10 ÷ 5 = 2
9 p = 9 x 2
9 p = 18
2 u + 4 = 9 p
2 u + 4 = 18
2 u = 18 - 4
2 u = 14
1 u = 14 ÷ 2 = 7
Total number of passengers at first
= 3 u
= 3 x 7
= 21
Answer(s): 21