Question

In how much time will a train cross the platform whose length is seven times the length of the train, given that the train crosses a standing man on the platform in 12 seconds.
1. 2 minute 24 seconds
2. 1 minute 36 seconds
3. 1 minute 24 seconds
4. 1 minute 54 seconds

Answer 1

Correct Answer - Option 2 : 1 minute 36 seconds

Given:

The train crosses a standing man on the platform in 12 seconds

Concept Used:

Time taken by train to cross a pole/standing man/a point = Time taken by train to cross its own length

Time = Distance/Speed

Calculation:

Time taken by train to cross standing man = 12 seconds 

Let the length of train be x m

Length of platform will be 7x m according to the question.

Speed of train = [Distance (i.e length of the train)]/Time

⇒ Speed of train = x/12 m/sec

Time taken to cross the platform = (Distance [Length of train + platform])/Speed of train

⇒ Time taken to cross the platform = (x + 7x)/(x/12) = 8x/(x/12)

⇒ Time taken to cross the platform = 96 seconds = 1 minute 36 seconds

∴ Time taken is 1 minute 36 seconds