The speed of a boat in still water is 30 km h and the rate of the current is 6 km h. The distance (in km) travelled upstream in 5 minutes is:

Options

A. 3
B. 4
C. 2
D. 2.5

Answer

To solve the problem step by step, we will follow these calculations:

1. **Identify the speed of the boat and the current:**
- Speed of the boat in still water = 30 km/h
- Speed of the current = 6 km/h

2. **Calculate the effective speed of the boat when traveling upstream:**
- The effective speed of the boat upstream is calculated by subtracting the speed of the current from the speed of the boat.
\[ \text{Effective speed upstream} = \text{Speed of the boat} - \text{Speed of the current} = 30 \text{ km/h} - 6 \text{ km/h} = 24 \text{ km/h} \]

3. **Convert the time from minutes to hours:**
- We need to find out how far the boat travels in 5 minutes. First, we convert 5 minutes into hours.
\[ \text{Time in hours} = \frac{5 \text{ minutes}}{60} = \frac{1}{12} \text{ hours} \]

4. **Calculate the distance traveled upstream in 5 minutes:**
- We use the formula for distance, which is:
\[ \text{Distance} = \text{Speed} \times \text{Time} \]
- Substituting the effective speed and the time we found:
\[ \text{Distance} = 24 \text{ km/h} \times \frac{1}{12} \text{ hours} = 2 \text{ km} \]

5. **Final answer:**
- The distance traveled upstream in 5 minutes is **2 km**.