Some children board a school bus.
At Bus Stop A,
13 of them alight
and 2 children board.
At Bus Stop B,
38 of the children alight
and 9 board.
If there are 19 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 + 2 |
|
After 1 |
2 u + 2 |
8 p |
Change 2 At Bus Stop B |
|
- 3 p + 9 |
After 2 |
|
19 |
Working backwards.
Number of children in the end = 19
8 p - 3 p = 19 - 9
5 p = 10
1 p = 10 ÷ 5 = 2
8 p = 8 x 2
8 p = 16
2 u + 2 = 8 p
2 u + 2 = 16
2 u = 16 - 2
2 u = 14
1 u = 14 ÷ 2 = 7
Total number of children at first
= 3 u
= 3 x 7
= 21
Answer(s): 21