A train 75 metres long is running with a speed of 20 km/hr. It will pass a standing man in-----

Options

A. 12 seconds
B. 13.5 seconds
C. 14 seconds
D. 15.5 seconds

Answer

To solve the problem of how long it takes for a train to pass a standing man, we can follow these steps:

### Step 1: Identify the given values
- Length of the train = 75 meters
- Speed of the train = 20 km/hr

### Step 2: Convert the speed from km/hr to m/s
To convert the speed from kilometers per hour to meters per second, we use the conversion factor:
\[ 1 \text{ km/hr} = \frac{5}{18} \text{ m/s} \]
Thus,
\[ \text{Speed in m/s} = 20 \text{ km/hr} \times \frac{5}{18} = \frac{100}{18} \approx 5.56 \text{ m/s} \]

### Step 3: Use the formula for time
The time taken to pass the man can be calculated using the formula:
\[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \]
Here, the distance is the length of the train (75 meters) and the speed is the converted speed (5.56 m/s).

### Step 4: Calculate the time
Substituting the values into the formula:
\[ \text{Time} = \frac{75 \text{ meters}}{5.56 \text{ m/s}} \approx 13.5 \text{ seconds} \]

### Conclusion
The train will pass the standing man in approximately **13.5 seconds**.

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