Some children board a school bus.
At Bus Stop A,
37 of them alight
and 5 children board.
At Bus Stop B,
57 of the children alight
and 3 board.
If there are 9 children on the bus now,
how many children are on the bus at first?
|
Number of children |
Before |
7 u |
|
Change 1 At Bus Stop A |
- 3 u + 5 |
|
After 1 |
4 u + 5 |
7 p |
Change 2 At Bus Stop B |
|
- 5 p + 3 |
After 2 |
|
9 |
Working backwards.
Number of children in the end = 9
7 p - 5 p = 9 - 3
2 p = 6
1 p = 6 ÷ 2 = 3
7 p = 7 x 3
7 p = 21
4 u + 5 = 7 p
4 u + 5 = 21
4 u = 21 - 5
4 u = 16
1 u = 16 ÷ 4 = 4
Total number of children at first
= 7 u
= 7 x 4
= 28
Answer(s): 28