Some students board a school bus.
At Bus Stop A,
13 of them alight
and 8 students board.
At Bus Stop B,
47 of the students alight
and 6 board.
If there are 18 students on the bus now,
how many students are on the bus at first?
|
Number of students |
Before |
3 u |
|
Change 1 At Bus Stop A |
- 1 u + 8 |
|
After 1 |
2 u + 8 |
7 p |
Change 2 At Bus Stop B |
|
- 4 p + 6 |
After 2 |
|
18 |
Working backwards.
Number of students in the end = 18
7 p - 4 p = 18 - 6
3 p = 12
1 p = 12 ÷ 3 = 4
7 p = 7 x 4
7 p = 28
2 u + 8 = 7 p
2 u + 8 = 28
2 u = 28 - 8
2 u = 20
1 u = 20 ÷ 2 = 10
Total number of students at first
= 3 u
= 3 x 10
= 30
Answer(s): 30