A train 270 m long is running over a bridge of length of 130 m with a speed of 40 m/s. What is the time taken by this train to cross the bridge?

Options

A. 6 s
B. 16 s
C. 10 s
D. none of these

Answer

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

### Step 1: Identify the lengths involved
- Length of the train = 270 m
- Length of the bridge = 130 m

### Step 2: Calculate the total distance to be covered
To find the total distance the train needs to cover to completely cross the bridge, we add the length of the train and the length of the bridge:
\[ \text{Total Distance} = \text{Length of Train} + \text{Length of Bridge} = 270 \, \text{m} + 130 \, \text{m} = 400 \, \text{m} \]

### Step 3: Identify the speed of the train
The speed of the train is given as:
\[ \text{Speed} = 40 \, \text{m/s} \]

### Step 4: Use the formula for time
The time taken to cross the bridge can be calculated using the formula:
\[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \]
Substituting the values we have:
\[ \text{Time} = \frac{400 \, \text{m}}{40 \, \text{m/s}} \]

### Step 5: Perform the calculation
Calculating the above expression gives:
\[ \text{Time} = 10 \, \text{seconds} \]

### Final Answer
The time taken by the train to cross the bridge is **10 seconds**.

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