Aptitude - Problems on Trains - Discussion

The Answer is 65s, because the question in not mention both pole and platform then why we calculate both?

Here, it should come 890 instead of 650. We should add both the values. So the correct answer is 89sec.

It should be 65 sec only.

Analysis: The speed of the train is the same in both cases. For the constant speed,

(distance/time) in first case = (distance/time) in second case.

240/24=650/x==> x = 65 sec.

240=24sec.
then 650=x.
240x=650*24,
240x/240=650*24/240,
= 65m/s.

240/24=10,
.:650/10=65+24=89.

Here, the question is asking for a specific time taken by the train to pass the platform (650/10 =65) not the total time is taken. If at all they asked for total time, we would add them up (65+24).

Distance= speed * time,
240/ 24=time,
Time = 10s,
Distance= speed* time.
240+ 650 combing distance = 890,
890/10= time,
89 m/s.

Why did you add 240?

Length of train(distance)=240m
Time=24sec
Formula: length(distance)=speed x time
240=speed x 24
speed=240/24
speed=10sec.

Now it has to pass platform of 650m
The total length of platform =650m
train length = 240m
The total distance the train pass the platform = 650+240=890m.
Because as the train entered the platform(650m) the train remaining part was outside the platform (240m).
So total distance the train cover is 890.

Why we are adding the time of poles with the time of platforms?