Aptitude - Problems on Trains - Discussion

If the time taken by train to cross the man is 20 sec then u people cal length of train as
distance = speed * time
= 15 m/s * 20 sec
= 300m
similarly it is also given that train crosses the platform in 30sec then why not the length of the train is
distance = speed * time
= 15 m/s * 36 sec
since both man an platform are stationary not moving . and the train is crossing the platform and man in same direction
explain me some one plz ..... i very poor in aptitude .. i cant understand the logic

Difference in time=16

So ,
(16/60)*54000m/60min

@frank.

Thats the brilliant answer dude.

Hai friends why (x+300)/36 = 15 ?

We have add platform lengthe(x) + tranin length(300) = total lenght (because the train enginee is pass the platform in 36 sec not tail of the train) Now we using m/s = speed formula to find unknown platform length

As man length is negligible than the train length so length of the train crossing the person is 15*20.

So time taken by the train is 20 sec and time taken by the train to cross the platform is 36 sec don't get get confused here.

Consider man is standing at the start of Platform,it takes 20 secs to cross man, but length of platorm is more than man.

Length of train = 15 * 20 = 300 m

But at 15 m/s train will last tip will take 16 more secs to cross platform i.e length of platform is 16 * 15 = 240 m

Length of man is negligible in comparison to the train, so if cal len = 20.

Then len will calculate to the train's actual lenght.

Hi 36*54*5/18=540-> which is nothing but the total length includes train and plat form....
and 20*54*5/18=300 -> which is lenth includes train and up to man ..... and taking difference 540-300=240

Hi Guys

speed=15 m/s
A train passes the platform in 36 secs
15*36=540
a man standing on the platform in 20 secs
15*20=300

540-300=240
Ans:240 Am I right