Ravi can row downstream at 9 km/h and upstream at 5 km/h. Find the speed of Ravi in still water and speed of current.

Options

A. 7 km/h and 2 km/h
B. 8 km/h and 6 km/h
C. 7 km/h and 3 km/h
D. 8 km/h and 2 km/h

Answer

To solve the problem, we need to find the speed of Ravi in still water and the speed of the current based on the given downstream and upstream speeds.

### Step-by-Step Solution:

1. **Identify the Given Data:**
- Downstream speed (ds) = 9 km/h
- Upstream speed (us) = 5 km/h

2. **Calculate the Speed of Ravi in Still Water:**
- The formula to find the speed of the boat (or in this case, Ravi) in still water is:
\[ \text{Speed of Ravi} = \frac{\text{Downstream speed} + \text{Upstream speed}}{2} \]
- Substituting the values:
\[ \text{Speed of Ravi} = \frac{9 + 5}{2} = \frac{14}{2} = 7 \text{ km/h} \]

3. **Calculate the Speed of the Current:**
- The formula to find the speed of the current is:
\[ \text{Speed of Current} = \frac{\text{Downstream speed} - \text{Upstream speed}}{2} \]
- Substituting the values:
\[ \text{Speed of Current} = \frac{9 - 5}{2} = \frac{4}{2} = 2 \text{ km/h} \]

4. **Final Answers:**
- Speed of Ravi in still water = 7 km/h
- Speed of the current = 2 km/h

### Summary:
- Speed of Ravi in still water = 7 km/h
- Speed of the current = 2 km/h

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