A car runs at 50 km/h when not serviced and at 60 km/h when serviced. After servicing, it covers a certain distance in 6 h (distance = 360 km). How long will it take to cover the same distance when not serviced at 50 km/h?

Introduction / Context:
The stem wording is commonly intended to compare the time for the same fixed distance under two speed conditions (serviced vs not serviced). We first find the route length using the serviced run, then compute the time at the lower “not serviced” speed for that same distance.

Given Data / Assumptions:

• Serviced speed = 60 km/h; serviced time = 6 h ⇒ distance D = 360 km.
• Not serviced speed = 50 km/h.
• We seek time at 50 km/h for D = 360 km.

Concept / Approach:
Use t = D / v with D fixed. Keep units in hours throughout to avoid conversion errors.

Step-by-Step Solution:

Verification / Alternative check:
At 60 km/h, 6 h is 360 km; at 50 km/h, 7.2 h also yields 360 km—consistent.

Why Other Options Are Wrong:
8 or 8.2 h overestimate; 6.5 h underestimates time for 50 km/h.

Common Pitfalls:
Misreading the stem to ask the time “when serviced” again; the meaningful comparison is serviced vs not serviced for the same distance.

Final Answer:
7.2 h