Aptitude - Problems on Trains - Discussion

Speed = total (distance/time).
240/24sec = 10 ms.
So, 650/10ms = 65 sec.

I have a simple solution.
Speed = distance/time;
240/24 = 10 m/s is speed of train.

Now pltform length is 650 m.
We have speed of train nd platform length.
so, time for crossing platform=length of platform/speed of train(t=d/s),
T(time for crossing platform)=650/10 = 65.

Here 65 is the time taken by the part of engine to cross the platform, not by the entire train.
24 second is time taken by train to reach to the pole + 65 sec is time tacken by train to cross the platform = 89 sec.

The solution is correct.

If we don't add 240 we will get only the time taken for the engine to travel and not the entire train.

So we have to add it.

Please let me know about the solution.

I'm not getting this. someone help me.

65 answer is correct.

I too get the answer as 65.

Pole:
Speed = lengh/time.
= 240/24,
= 10m/s.
Platform:

Time = length/speed.
= (240 + 650)/10,
= 89s.

In case of passing a pole,

length of the train = speed * time.
So speed = 240 ÷ 24,
=10 m/s.

In case of passing a platform,
Length of train + length of platform = speed * time.
then,
240 + 650 = 10 * time,
So, time = (240 + 650)/10,
= 89m/s.

Can anyone tell why we add 240, while the question is only for 650?

The answer should be 65 because in this question only asking about how much time take to pass 650 mtr platform not the both platform.

240 m passes in 24 sec.
1 m passes in 24/240.
890 m passes in 24 * 890/240 = 89 sec.