A car runs at 65 km/h when serviced and 40 km/h when not serviced. After servicing, the car covers a certain distance in 5 h (distance = 325 km). Approximately how long will it take to cover the same distance when not serviced at 40 km/h?

Introduction / Context:
Speed–time–distance conversions are direct when one of the trip legs provides the total distance. Here, we first compute the route length from the serviced run, then reuse that length to find the required time at the lower speed. The question seeks an approximate time, so rounding to the nearest option is appropriate.

Given Data / Assumptions:

• Serviced speed = 65 km/h; time = 5 h.
• Distance D = 65 * 5 = 325 km.
• Not serviced speed = 40 km/h.

Concept / Approach:
Time = distance / speed. Compute 325 / 40 hours, then compare to the nearest choice as “approximate”.

Step-by-Step Solution:

Verification / Alternative check:
At 40 km/h for 8.125 h you cover exactly 325 km; rounding to 8 h is within the intent of “approximate”.

Why Other Options Are Wrong:
7 h gives 280 km; 10 h gives 400 km—both far from 325 km.

Common Pitfalls:
Mistaking “approximate” for percentage rounding; ensure you use the same distance for both conditions.

Final Answer:
8 h