Some students board a school bus.
At Bus Stop A,
16 of them alight
and 5 students board.
At Bus Stop B,
13 of the students alight
and 9 board.
If there are 19 students on the bus now,
how many students are on the bus at first?
|
Number of students |
Before |
6 u |
|
Change 1 At Bus Stop A |
- 1 u + 5 |
|
After 1 |
5 u + 5 |
3 p |
Change 2 At Bus Stop B |
|
- 1 p + 9 |
After 2 |
|
19 |
Working backwards.
Number of students in the end = 19
3 p - 1 p = 19 - 9
2 p = 10
1 p = 10 ÷ 2 = 5
3 p = 3 x 5
3 p = 15
5 u + 5 = 3 p
5 u + 5 = 15
5 u = 15 - 5
5 u = 10
1 u = 10 ÷ 5 = 2
Total number of students at first
= 6 u
= 6 x 2
= 12
Answer(s): 12