Some children board a school bus.
At Bus Stop A,
37 of them alight
and 4 children board.
At Bus Stop B,
38 of the children alight
and 5 board.
If there are 15 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 + 4 |
|
After 1 |
4 u + 4 |
8 p |
Change 2 At Bus Stop B |
|
- 3 p + 5 |
After 2 |
|
15 |
Working backwards.
Number of children in the end = 15
8 p - 3 p = 15 - 5
5 p = 10
1 p = 10 ÷ 5 = 2
8 p = 8 x 2
8 p = 16
4 u + 4 = 8 p
4 u + 4 = 16
4 u = 16 - 4
4 u = 12
1 u = 12 ÷ 4 = 3
Total number of children at first
= 7 u
= 7 x 3
= 21
Answer(s): 21