Aptitude - Problems on Trains - Discussion

As they asked only platform length why isn't it 35X15=540...
why should we substract...??

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.