Some children board a school bus.
At Bus Stop A,
49 of them alight
and 10 children board.
At Bus Stop B,
35 of the children alight
and 7 board.
If there are 17 children on the bus now,
how many children are on the bus at first?
|
Number of children |
Before |
9 u |
|
Change 1 At Bus Stop A |
- 4 u + 10 |
|
After 1 |
5 u + 10 |
5 p |
Change 2 At Bus Stop B |
|
- 3 p + 7 |
After 2 |
|
17 |
Working backwards.
Number of children in the end = 17
5 p - 3 p = 17 - 7
2 p = 10
1 p = 10 ÷ 2 = 5
5 p = 5 x 5
5 p = 25
5 u + 10 = 5 p
5 u + 10 = 25
5 u = 25 - 10
5 u = 15
1 u = 15 ÷ 5 = 3
Total number of children at first
= 9 u
= 9 x 3
= 27
Answer(s): 27