Some children board a school bus.
At Bus Stop A,
35 of them alight
and 9 children board.
At Bus Stop B,
13 of the children alight
and 8 board.
If there are 18 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 |
- 3 u + 9 |
|
After 1 |
2 u + 9 |
3 p |
Change 2 At Bus Stop B |
|
- 1 p + 8 |
After 2 |
|
18 |
Working backwards.
Number of children in the end = 18
3 p - 1 p = 18 - 8
2 p = 10
1 p = 10 ÷ 2 = 5
3 p = 3 x 5
3 p = 15
2 u + 9 = 3 p
2 u + 9 = 15
2 u = 15 - 9
2 u = 6
1 u = 6 ÷ 2 = 3
Total number of children at first
= 5 u
= 5 x 3
= 15
Answer(s): 15