Some children board a school bus.
At Bus Stop A,
15 of them alight
and 8 children board.
At Bus Stop B,
47 of the children alight
and 4 board.
If there are 16 children on the bus now,
how many children are on the bus at first?
|
Number of children |
Before |
5 u |
|
Change 1 At Bus Stop A |
- 1 u + 8 |
|
After 1 |
4 u + 8 |
7 p |
Change 2 At Bus Stop B |
|
- 4 p + 4 |
After 2 |
|
16 |
Working backwards.
Number of children in the end = 16
7 p - 4 p = 16 - 4
3 p = 12
1 p = 12 ÷ 3 = 4
7 p = 7 x 4
7 p = 28
4 u + 8 = 7 p
4 u + 8 = 28
4 u = 28 - 8
4 u = 20
1 u = 20 ÷ 4 = 5
Total number of children at first
= 5 u
= 5 x 5
= 25
Answer(s): 25