Aptitude - Problems on Trains - Discussion

Hey, Dude, I am here to clarify your Doubt.
Here Given data is :
Length of the Train = 240m.

Time is taken by the train to cross the pole = 24sec.
so speed of the train = distance/time.
=> 240/24 = 10m/s.

Therefore train speed = 10m/s.
And Length of the platform = 650m.

So we can add the length of train+length of the platform=240+650 = 890m.

bcoz train passes the platform that y we can add both the lengths here.
time is taken by train to cross the platform=total distance/speed.

So 890/10 = 89sec.

We add both the length of the train and platform because the train has to cross also its tail from the platform. If, the only head of train (engine) crosses the platform its other parts remain on the platform.

Train Length 240m long.
Time to pass pole = 24 second.

Speed= 240/24=10 m/s.

For length 650 m = 240+650=890m.
Speed = 890/10=89.

I get confuse. What is the correct answer?

Speed=(lt+lp)/time.
lt = length of the train.
lp = lenght of the platform.

Without adding platform length the train speed?
Seed=(240)/24.
Speed=24m/s.
with platform length.
Time=(240+650)/10.
Time=89sec.

Can we add 650+240+240? Because the train crosses between the two ends of the platform.

@Nithu.

When the train passes from the platform then the length of the train from start to end will pass the platform at the specific speed. So the train length will be added with a platform.

Here 240 is added to the length 650 because it's the length of the train in the question they given the pole is crossed in 24 seconds because we can find the length of the train using the time taken to cross the pole(where the pole length is negligible) so to calculate the time required is;

240(length of the train) + 650(length of the platform) = 890m,
890/10 = 89s.

Speed= Distance *Time then how come 240/24?

Please explain in detail.

Thank you @Sohail khan.