Aptitude - Problems on Trains - Discussion

Hi Guys

1 Km=1000 Meters
1 hr=3600 seconds

If the speed of the train is 54 km/hr
54*1000= 54000
54000/3600=15
A train passes a station platform in 36 seconds
15*36=540
a man standing on the platform in 20 seconds
15*20=300

540-300=240
Ans:240 Simple

I solved in dis manner
54*(5/18)=15
speed =15m/sec
it crossed d platform within 36 secs
for 20 sec=?
36-20=16
16*15=240m

@divya :yeah... Its good..

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