Speed of a boat along the current and against the current are 11 km/hr and 6 km/hr respectively. What is the speed (in km/hr) of the current?

Options

A. 1.5
B. 2.5
C. 3
D. 4.5

Answer

To find the speed of the current, we can use the relationship between the speed of the boat downstream (along the current), upstream (against the current), and the speed of the current itself.

### Step-by-Step Solution:

1. **Identify the speeds**:
- Speed of the boat downstream (along the current) = 11 km/hr
- Speed of the boat upstream (against the current) = 6 km/hr

2. **Use the formula for the speed of the current**:
The speed of the current (C) can be calculated using the formula:
\[ C = \frac{(D - U)}{2} \]
where D is the downstream speed and U is the upstream speed.

3. **Substitute the values into the formula**:
\[ C = \frac{(11 \text{ km/hr} - 6 \text{ km/hr})}{2} \]

4. **Calculate the difference**:
\[ C = \frac{5 \text{ km/hr}}{2} \]

5. **Final calculation**:
\[ C = 2.5 \text{ km/hr} \]

Thus, the speed of the current is **2.5 km/hr**.