Final answer:
The expression for the position of the taxi in terms of t is x * t + 320 km.
Step-by-step explanation:
To write an expression, in terms of t, for the position of the taxi, we need to consider the movements of the truck, car, and taxi.
Let's assume that the truck is moving at a constant speed of 60 km/h to the west, and the car is moving at a constant speed of 40 km/h to the east.
When t = 8, the car will be 8 * 40 = 320 km east of its initial position.
To ensure that the taxi is never in the same position as the truck, we can assume that the taxi is also moving at a constant speed, but in the opposite direction of the truck.
Let's say the taxi is moving at a speed of x km/h to the east.
Therefore, the expression for the position of the taxi in terms of t is: x * t + 320 km