Some children board a school bus.
At Bus Stop A,
35 of them alight
and 10 children board.
At Bus Stop B,
25 of the children alight
and 7 board.
If there are 19 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 + 10 |
|
After 1 |
2 u + 10 |
5 p |
Change 2 At Bus Stop B |
|
- 2 p + 7 |
After 2 |
|
19 |
Working backwards.
Number of children in the end = 19
5 p - 2 p = 19 - 7
3 p = 12
1 p = 12 ÷ 3 = 4
5 p = 5 x 4
5 p = 20
2 u + 10 = 5 p
2 u + 10 = 20
2 u = 20 - 10
2 u = 10
1 u = 10 ÷ 2 = 5
Total number of children at first
= 5 u
= 5 x 5
= 25
Answer(s): 25