Question

Vehicle A is driving east from a set start point along a road at 56 km/h. Vehicle B is driving B is driving west along the same road from the same starting point at 68 km/h. After one hour, what is the position of Vehicle B relative to Vehicle A?

a. 12 km West
b. 12 km East
c. 124 km West
d. 124 km East

Answer 1

124 km west

Step-by-step explanation:

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Answer 2

c. 124 km West

Step-by-step explanation:

Take east to be positive and west to be negative.

The position of Vehicle A at time t is:

A = 56t

The position of Vehicle B at time t is:

B = -68t

The position of B relative to A is:

B − A = -68t − 56t

B − A = -124t

After 1 hour, the displacement is:

B − A = -124

B − A = 124 km west