A boat’s speed in still water is 6 km/h and the stream’s speed is 1.5 km/h. The man rows to a place 22.5 km away and returns to the start. Find the total time taken (in hours and minutes).

Introduction / Context:
Compute leg times with effective upstream and downstream speeds and sum them to get the total duration.

Given Data / Assumptions:

• b = 6 km/h; c = 1.5 km/h
• Downstream speed vd = 7.5 km/h
• Upstream speed vu = 4.5 km/h
• Distance each way = 22.5 km

Concept / Approach:
Total time = 22.5/7.5 + 22.5/4.5 (hours).

Step-by-Step Solution:

Verification / Alternative check:
All values align with b ± c; no inconsistencies appear.

Why Other Options Are Wrong:
Any other total would not match both leg computations given the fixed speeds and distance.

Common Pitfalls:
Averaging the two speeds to get a single speed for the round trip is invalid; use time per leg instead.

Final Answer:
8 hrs.