Some children board a school bus.
At Bus Stop A,
13 of them alight
and 5 children board.
At Bus Stop B,
35 of the children alight
and 4 board.
If there are 18 children on the bus now,
how many children are on the bus at first?
|
Number of children |
Before |
3 u |
|
Change 1 At Bus Stop A |
- 1 u + 5 |
|
After 1 |
2 u + 5 |
5 p |
Change 2 At Bus Stop B |
|
- 3 p + 4 |
After 2 |
|
18 |
Working backwards.
Number of children in the end = 18
5 p - 3 p = 18 - 4
2 p = 14
1 p = 14 ÷ 2 = 7
5 p = 5 x 7
5 p = 35
2 u + 5 = 5 p
2 u + 5 = 35
2 u = 35 - 5
2 u = 30
1 u = 30 ÷ 2 = 15
Total number of children at first
= 3 u
= 3 x 15
= 45
Answer(s): 45