The speed of a boat in still water is 2 km/hr. If its speed upstream be 1 km/hr, then speed of the stream is -----

Options

A. 1.5 km/hr
B. 3 km/hr
C. 1 km/hr
D. None of these

Answer

To find the speed of the stream, we can use the relationship between the speed of the boat in still water, the speed of the boat upstream, and the speed of the stream.

### Given:
- Speed of the boat in still water (B) = 2 km/hr
- Speed of the boat upstream (U) = 1 km/hr

### Step 1: Understanding the relationship
The speed of the boat upstream is affected by the speed of the stream. The formula to calculate the speed of the boat upstream is:
\[ U = B - S \]
where:
- \( U \) = speed of the boat upstream
- \( B \) = speed of the boat in still water
- \( S \) = speed of the stream

### Step 2: Substitute the known values
We can substitute the known values into the equation:
\[ 1 = 2 - S \]

### Step 3: Solve for the speed of the stream (S)
Rearranging the equation to solve for \( S \):
\[ S = 2 - 1 \]
\[ S = 1 \text{ km/hr} \]

### Conclusion
The speed of the stream is **1 km/hr**.

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