Aptitude - Problems on Trains - Discussion

It will take 89 seconds for the train to pass the platform.

89 is the correct answer.

There is no need to add both lengths.
The question is only for the platform. So why do we add both?

Please anyone explain to me?

The train is 240 meters long, and the platform is 650 meters long.

When a train passes a platform, it must cover both its own length and the length of the platform.

So total distance=240 + 650 = 890meters.

Given answer 89 is correct. I too agree.

@All.

What I understand is the train starting point and cross-platform is 650 meters. The train exit point after crossing the platform is 240 meters so you should add 240 + 650.

To solve this, we need to consider the additional distance the train needs to cover to pass the platform.

First, let's find the speed of the train:

Speed = Distance/Time.
Speed = 240 m/24 s.
Speed = 10 m/s.

Now, the train needs to cover the length of the platform (650 m) plus its length (240 m) relative to the platform. So, the total distance to cover is 650 m + 240 m = 890 m.

Time = Distance/Speed.
Time = 890 m/10 m/s.
Time = 89 seconds.

So, it will take 89 seconds for the train to pass the platform.

WHY NOT 65?
We got train speed =10.
Then we can directly find the time right?
i.e time = 65 because t=d/s=>650/10 = 65.

I think the length of a platform is greater than the length of the trian so to pass the platform we should be adding each lengths.

The length of the train = 240m.
time to cross the pole = 24sec.
Length of the station =650m.

so,
The speed of the train = length of the train /time to cross the pole * 18/5.
So,
= 240/24*18/5
= 10*18/5
= 180/5.
The speed of the train = 36km/h.

And the time to cross the station = 240+650/36*18/5.
= 890*18/36*5
= 16020/180.
Final answer = 89sec.
So, option B is the right answer.