Some adults board a school bus.
At Bus Stop A,
14 of them alight
and 5 adults board.
At Bus Stop B,
310 of the adults alight
and 4 board.
If there are 18 adults on the bus now,
how many adults are on the bus at first?
|
Number of adults |
Before |
4 u |
|
Change 1 At Bus Stop A |
- 1 u + 5 |
|
After 1 |
3 u + 5 |
10 p |
Change 2 At Bus Stop B |
|
- 3 p + 4 |
After 2 |
|
18 |
Working backwards.
Number of adults in the end = 18
10 p - 3 p = 18 - 4
7 p = 14
1 p = 14 ÷ 7 = 2
10 p = 10 x 2
10 p = 20
3 u + 5 = 10 p
3 u + 5 = 20
3 u = 20 - 5
3 u = 15
1 u = 15 ÷ 3 = 5
Total number of adults at first
= 4 u
= 4 x 5
= 20
Answer(s): 20