Some children board a school bus.
At Bus Stop A,
25 of them alight
and 3 children board.
At Bus Stop B,
13 of the children alight
and 2 board.
If there are 10 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 |
- 2 u + 3 |
|
After 1 |
3 u + 3 |
3 p |
Change 2 At Bus Stop B |
|
- 1 p + 2 |
After 2 |
|
10 |
Working backwards.
Number of children in the end = 10
3 p - 1 p = 10 - 2
2 p = 8
1 p = 8 ÷ 2 = 4
3 p = 3 x 4
3 p = 12
3 u + 3 = 3 p
3 u + 3 = 12
3 u = 12 - 3
3 u = 9
1 u = 9 ÷ 3 = 3
Total number of children at first
= 5 u
= 5 x 3
= 15
Answer(s): 15