A train moves at the speed of 40 m/s and crosses a bridge of length 550 metres in 25 seconds. What is the length (in metres) of the train?

Options

A. 400
B. 450
C. 480
D. 550

Answer

To find the length of the train, we can follow these steps:

### Step 1: Calculate the total distance covered by the train while crossing the bridge.
The total distance covered by the train while crossing the bridge is equal to the length of the bridge plus the length of the train itself.

### Step 2: Use the formula for distance.
The formula for distance is:
\[ \text{Distance} = \text{Speed} \times \text{Time} \]

Given:
- Speed of the train = 40 m/s
- Time taken to cross the bridge = 25 seconds

We can calculate the total distance covered by the train:
\[ \text{Total Distance} = 40 \, \text{m/s} \times 25 \, \text{s} \]

### Step 3: Perform the calculation.
Calculating the total distance:
\[ \text{Total Distance} = 40 \times 25 = 1000 \, \text{metres} \]

### Step 4: Set up the equation for the length of the train.
Let the length of the train be \( L \). According to our earlier statement:
\[ \text{Total Distance} = \text{Length of the Bridge} + \text{Length of the Train} \]
\[ 1000 = 550 + L \]

### Step 5: Solve for the length of the train.
Rearranging the equation to find \( L \):
\[ L = 1000 - 550 \]
\[ L = 450 \, \text{metres} \]

### Conclusion:
The length of the train is 450 metres.

---