Some adults board a school bus.
At Bus Stop A,
13 of them alight
and 4 adults board.
At Bus Stop B,
710 of the adults alight
and 6 board.
If there are 12 adults on the bus now,
how many adults are on the bus at first?
|
Number of adults |
Before |
3 u |
|
Change 1 At Bus Stop A |
- 1 u + 4 |
|
After 1 |
2 u + 4 |
10 p |
Change 2 At Bus Stop B |
|
- 7 p + 6 |
After 2 |
|
12 |
Working backwards.
Number of adults in the end = 12
10 p - 7 p = 12 - 6
3 p = 6
1 p = 6 ÷ 3 = 2
10 p = 10 x 2
10 p = 20
2 u + 4 = 10 p
2 u + 4 = 20
2 u = 20 - 4
2 u = 16
1 u = 16 ÷ 2 = 8
Total number of adults at first
= 3 u
= 3 x 8
= 24
Answer(s): 24