A train 300 metres long passes a standing man is 15 seconds. The speed of the train is -----

Options

A. 40 km/hr
B. 50 km/hr
C. 60 km/hr
D. 72 km/hr

Answer

To find the speed of the train, we will follow these steps:

### Step 1: Identify the given information
- Length of the train = 300 meters
- Time taken to pass the standing man = 15 seconds

### Step 2: Use the formula for speed
The formula for speed is given by:
\[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} \]

### Step 3: Calculate the speed in meters per second
Here, the distance is the length of the train (300 meters) and the time is 15 seconds. Plugging in the values:
\[ \text{Speed} = \frac{300 \text{ meters}}{15 \text{ seconds}} \]
\[ \text{Speed} = 20 \text{ m/s} \]

### Step 4: Convert the speed to kilometers per hour
To convert meters per second to kilometers per hour, we use the conversion factor:
\[ 1 \text{ m/s} = \frac{18}{5} \text{ km/h} \]
So, we multiply the speed in m/s by \(\frac{18}{5}\):
\[ \text{Speed in km/h} = 20 \text{ m/s} \times \frac{18}{5} \]
\[ \text{Speed in km/h} = 20 \times 3.6 = 72 \text{ km/h} \]

### Step 5: State the final answer
The speed of the train is **72 km/h**.

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