Question

What is the speed of the boat in still water? 
Statement I - The boat covers a distance of 48 km in 6 hours while running upstream. 
Statement II - The boat covers the same distance in 4 hours while running downstream.

• A. If the question can be answered with the help of statement I alone.
• B. If the question can be answered with the help of statement II alone.
• C. If both, statement I and statement II are needed to answer the question.
• D. If the question cannot be answered even with the help of both the statements.

Hint:

In boat-related problems, use the difference between upstream and downstream speeds to calculate the speed in still water.

Answer 1

The Correct Option is C

From Statement I:
The boat covers 48 km in 6 hours upstream. This gives the speed of the boat in upstream (speed = distance/time = 48/6 = 8 km/h).
However, we still don’t know the speed of the boat in still water, as we need the speed of the current to calculate that.
From Statement II: The boat covers the same distance in 4 hours downstream. This gives the speed of the boat in downstream (speed = distance/time = 48/4 = 12 km/h).
To find the speed of the boat in still water, we need both the upstream and downstream speeds to use the formula for the speed in still water.
Combining both statements: Using the formula \( {Speed in still water} = \frac{{Upstream speed} + {Downstream speed}}{2} \), we can find the speed of the boat in still water.
This requires both upstream and downstream speeds. Thus, both statements are needed to answer the question.