Aptitude - Problems on Trains - Discussion

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.

To solve this problem, we need to first determine the speed of the train. We can use the formula:

Speed = Distance/Time.

From the given information, we know that the length of the train is 240 meters and it passes a pole in 24 seconds. Therefore, the speed of the train is:

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

Now, we need to find out how long it will take for the train to pass a platform that is 650 meters long. Let's assume that the front of the train just reaches the beginning of the platform at time t=0.

As the train passes over the entire length of the platform, it will cover a distance equal to the sum of the length of the train and the length of the platform.
Total distance to be covered = 240 + 650 = 890 meters

To find the time taken for the train to cover this distance, we can use the formula:

Time = Distance / Speed

Time = 890 / 10
Time = 89 seconds

Therefore, it will take the train 89 seconds to pass a platform that is 650 meters long.

Here is the solution

Just apply required time formula.
Required time = distance /speed.

In this case, train Len = 240 + platform = 650/speed.
And req tiime = 240 + 650/10 = 89 m/s thats it.