Aptitude - Problems on Trains - Discussion

If it is 24sec, then time taken by faster train will be also 24.

But how is it possible that both are same. Not getting.

See we can't add the lengths of two train because here there is no concept of crossing the train. When the driver of slower train would reach the end of faster train the both train will be symmetric. Means at the same time the driver of faster train would be at the end of slower train.

We would have added the lengths if asked about the crossing of guards in the last coaches.

Nothing tricky. We have to understand the concept of relative speed.

Keeping the faster train static we can consider the speed of slower train as (30+45) km/hr and as train has to pass the driver. Distance taken is 500m.

Speed=75km/hr=75*5/18m/sec.

Time taken=24sec.

Its tricky one. I made mistake in first attempt. Because I didn't read the Question well and assumed that it is asking 4 the time taken to cross each other.

Good one.

We should understand the Question well before attempting it.

Thank you sundar.

Very tricky Example...

Good one...

For the complete train to cross each other, it takes 48 sec.

To cross only the initial phase i.e. engine of first train facing the end of the second train. and engine of second train facing the end of the first train,it takes the half of the time to cross the complete train i.e. 48sec/2=24 sec.

Ans is correct. I did mistake at first time also.

It is a good one.

This is wrong. Try formula number 8 in formula section. We shoud use distance 1000.

@All

Initially I was confused same like you. But, the given answer is correct.

We can assume the given question as:

A man running 45 km/hr opposite direction (against) to a train running 30 km/hr. Find the time taken by train to pass the man.

In the case of Man, Point, Pole.. the length will be considered as 0.

Note: In the given questions, IF it is mentioned like 'both train are running in SAME direction'.... then we can include the both train length (as Chandana said).

I hope this will help you a little bit. Have a nice day!