A boat runs 16 km downstream in 2 hours and the same distance upstream in 4 hours. What is the speed of the boat in still water?

Q: A boat runs 16 km downstream in 2 hours and the same distance upstream in 4 hours. What is the speed of the boat in still water?

Given data Downstream speed d = 16/2 = 8 km/h Upstream speed u = 16/4 = 4 km/h Concept / Approach Still-water speed v = (u + d)/2. Step-by-step calculation v = (8 + 4)/2 = 6 km/h Final Answer 6 km/h

Difficulty: Easy

5 km/h
6 km/h
7 km/h
8 km/h

Correct Answer: 6 km/h

Explanation:

Given data

Downstream speed d = 16/2 = 8 km/h
Upstream speed u = 16/4 = 4 km/h

Concept / Approach

Still-water speed v = (u + d)/2.

Step-by-step calculation
v = (8 + 4)/2 = 6 km/h

Final Answer
6 km/h

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