Aptitude - Problems on Trains - Discussion

For 240m = 24sec.
==> 1m = 1/10 sec.

Total distance need to travel is (240+650) = 890m.
==>For 890m = 890/10 sec,
= 89Sec.

There is no need to add both lengths.
The question is only for the platform. So why do we add both?

Please anyone explain to me?

@All.

What I understand is the train starting point and cross-platform is 650 meters. The train exit point after crossing the platform is 240 meters so you should add 240 + 650.

Guys.. i can suggest u one thng that don't depend entirely on formulas, try

to analyze these type of problems logically..

coming to the prblm..

length of train = 240 mts

time taken to cross reference point(pole) = 24 sec

by the basic formula speed=length/time= (240/24) = 10 m/sec

they are asking the time taken by the train to cross the platform

imagine

------------------------- its a platform
650 m
______________ its train
240 m

train is said to be crossed the platform only if the entire train has pased over from it ryt... so clearly the total length that has to be travel to cross the platform is= (platform length + train length)

i.e. 650+240=890 m/sec

and again from the basic formula time= length/speed = 890/10 = 89 sec

@All.

Why we take (240+ 65)?
I think 240/24 =10m/sec,
Platform length= 650,
Time= 650/10 = 65.

The train 240 metres long, passes a stationary point in 24 seconds.

It passes the distance its own length of 240 metres in 24 seconds.

So, it passes 240 metres in 24 seconds.
Its speed is = 240 metres in 24 seconds.
=240 / 24 = 10 metres /second.

To pass a platform of length 650 metres, it should pass the platform and its own length of 240 metres, (to clear the platform),.

So, it should pass 650+240 = 890 metres.

At a speed of 10 metres per second, it will cross 890 metres in 89 seconds.

I think there's no need to add 240. They have only asked what's the time to cross platform. Thus the answer must me 65secs.

Thanks for explaining that option B is correct.

No. It not pass poles and platform. It pass only platform. 240m is train length.

Please explain all in details.

I'm not getting.