A 360-metre-long train crosses a platform in 120 seconds. What is the speed of the train ?

Options

A. 3 m/s
B. 5 m/s
C. 4.5 m/s
D. Cannot be determined

Explanation

To solve the problem of finding the speed of the train that crosses a platform in a given time, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Given Information:**
- Length of the train (LT) = 360 meters
- Time taken to cross the platform (T) = 120 seconds

2. **Understanding the Problem:**
- When the train crosses the platform, it covers its own length plus the length of the platform. However, since the length of the platform is not provided, we cannot calculate the total distance covered by the train.

3. **Calculate the Speed:**
- Speed (S) is defined as:
\[ S = \frac{\text{Total Distance}}{\text{Time}} \]
- The total distance covered by the train while crossing the platform is the length of the train plus the length of the platform (D):
\[ \text{Total Distance} = D + 360 \]
- Therefore, the speed can be expressed as:
\[ S = \frac{D + 360}{120} \]

4. **Conclusion:**
- Since we do not have the value of D (the length of the platform), we cannot determine the exact speed of the train. Thus, we conclude that the speed of the train cannot be determined without knowing the length of the platform.

### Final Answer:
- The speed of the train cannot be determined without the length of the platform.