A train running at the speed of 45 kmph took 12 seconds in passing a certain point. The the length of the train must be -----

Options

A. 90 metres
B. 120 metres
C. 150 metres
D. 540 metres

Answer

To find the length of the train, we can use the formula:

**Distance = Speed × Time**

### Step 1: Convert the speed from km/h to m/s
The speed of the train is given as 45 km/h. To convert this speed into meters per second (m/s), we use the conversion factor:

1 km/h = (1000 meters) / (3600 seconds) = 1/3.6 m/s.

So, we convert 45 km/h to m/s:

\[ \text{Speed in m/s} = 45 \times \frac{1}{3.6} = 12.5 \text{ m/s} \]

### Step 2: Calculate the distance (length of the train)
Now that we have the speed in m/s, we can calculate the distance (length of the train) using the time it took to pass the point, which is 12 seconds.

Using the formula:

\[ \text{Distance} = \text{Speed} \times \text{Time} \]

Substituting the values we have:

\[ \text{Distance} = 12.5 \text{ m/s} \times 12 \text{ s} = 150 \text{ meters} \]

### Conclusion
The length of the train is **150 meters**.

---