Two trains, each 50 m long are travelling in opposite direction with velocity 10 m/s and 15 m/s. The time of crossing is

Options

A. 2s
B. 4s
C. `2sqrt(3)s`
D. `4sqrt(3)` s

Explanation

To solve the problem of two trains crossing each other, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Length of Each Train**:
- Each train is 50 meters long.

2. **Calculate the Total Distance to be Covered**:
- Since both trains are crossing each other, the total distance to be covered when they completely pass each other is the sum of their lengths.
- Total Distance = Length of Train 1 + Length of Train 2 = 50 m + 50 m = 100 m.

3. **Determine the Speeds of the Trains**:
- Train 1 is traveling at 10 m/s.
- Train 2 is traveling at 15 m/s.

4. **Calculate the Relative Speed**:
- Since the trains are moving in opposite directions, their speeds add up.
- Relative Speed = Speed of Train 1 + Speed of Train 2 = 10 m/s + 15 m/s = 25 m/s.

5. **Use the Formula for Time**:
- We can use the formula:
\[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \]
- Here, Distance = 100 m and Speed = 25 m/s.
- Therefore,
\[ \text{Time} = \frac{100 \text{ m}}{25 \text{ m/s}} = 4 \text{ seconds}. \]

### Final Answer:
The time taken for the two trains to cross each other is **4 seconds**.

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