Some students board a school bus.
At Bus Stop A,
25 of them alight
and 3 students board.
At Bus Stop B,
13 of the students alight
and 6 board.
If there are 20 students on the bus now,
how many students are on the bus at first?
|
Number of students |
Before |
5 u |
|
Change 1 At Bus Stop A |
- 2 u + 3 |
|
After 1 |
3 u + 3 |
3 p |
Change 2 At Bus Stop B |
|
- 1 p + 6 |
After 2 |
|
20 |
Working backwards.
Number of students in the end = 20
3 p - 1 p = 20 - 6
2 p = 14
1 p = 14 ÷ 2 = 7
3 p = 3 x 7
3 p = 21
3 u + 3 = 3 p
3 u + 3 = 21
3 u = 21 - 3
3 u = 18
1 u = 18 ÷ 3 = 6
Total number of students at first
= 5 u
= 5 x 6
= 30
Answer(s): 30