Some children board a school bus.
At Bus Stop A,
47 of them alight
and 11 children board.
At Bus Stop B,
310 of the children alight
and 5 board.
If there are 19 children on the bus now,
how many children are on the bus at first?
|
Number of children |
Before |
7 u |
|
Change 1 At Bus Stop A |
- 4 u + 11 |
|
After 1 |
3 u + 11 |
10 p |
Change 2 At Bus Stop B |
|
- 3 p + 5 |
After 2 |
|
19 |
Working backwards.
Number of children in the end = 19
10 p - 3 p = 19 - 5
7 p = 14
1 p = 14 ÷ 7 = 2
10 p = 10 x 2
10 p = 20
3 u + 11 = 10 p
3 u + 11 = 20
3 u = 20 - 11
3 u = 9
1 u = 9 ÷ 3 = 3
Total number of children at first
= 7 u
= 7 x 3
= 21
Answer(s): 21