Question

A 300 meters long train passes 450 meters long platform in 30 seconds. In how much time the train will pass a 700-meter long bridge?
1. 30 sec
2. 40 sec
3. 42 sec
4. 60 sec
5. 25 sec

Answer 1

Correct Answer - Option 2 : 40 sec

Given:

The length of the train is 300 meters.

The train can pass 450 meters long platforms in 30 seconds.

Formula used:

The speed of the train = {(the length of the train + the length of the platform or bridge or another train)/time}

Distance = Time × Speed

Calculation:

The speed of the train = {(300 + 450)/30} m/s

⇒ The speed of the train = {750/30} m/s

⇒ The speed of the train = 25 m/s

Now, to cross the 700-meter long bridge the train has to be travelled (700 + 300) meters = 1000 meters

So, required time = 1000/25 sec = 40 sec

∴ The train will pass the 700 meters long bridge in 40 seconds.