Aptitude - Problems on Trains - Discussion

Discussion Forum : Problems on Trains - General Questions (Q.No. 5)
5.
A train passes a station platform in 36 seconds and a man standing on the platform in 20 seconds. If the speed of the train is 54 km/hr, what is the length of the platform?
120 m
240 m
300 m
None of these
Answer: Option
Explanation:

Speed = 54 x 5 m/sec = 15 m/sec.
18

Length of the train = (15 x 20)m = 300 m.

Let the length of the platform be x metres.

Then, x + 300 = 15
36

x + 300 = 540

x = 240 m.

Discussion:
282 comments Page 11 of 29.

Uvesh said:   9 years ago
I did it like this.

First, while train passing thru platform in 36 sec = 15 x 36 = 540,
Second while train passing thru man in 20sec = 15 x 20 = 300,
Now, the relative length 540 - 300 = 240.

Peter said:   10 years ago
Easily way.

Train speed is 54 in KM/HR so KM/HR = 1000 M /3600 S = 10/36 = 5/18 * 54 train speed = 15 M/S.

Train crossed in 36 man in 20 so we can minus both so 36 - 20 = 16.
16 * 15 = 240.

Krishna said:   8 years ago
Here, the length of the train is more than the length of the platform, how can a train be fit on that platform?

Platform length is 240m and Train length is 300m. Please explain me about it.

Srinivas said:   1 decade ago
Actually, here it is asked for platform and train passed the platform. It doesn't matter train passed the man's distance. It's simple L = S*T but why you are including passed by man's time?

Bhaskar said:   9 years ago
When the train enters fully from where the platform begins and at the beginning point where the man is standing it takes 20 sec so,

=54*5/18*20= 300 and that is the length of the train.

Lokesh said:   3 years ago
Given the speed of the train is 54 km/hr.

In 60*60second.
15m in 1 seconds.
90m in 6 seconds.
150m in 10 seconds.
240m in 16 seconds.

Because the time diff is 16 seconds Platform length.
(30)

Shivam singh said:   8 years ago
Km/h to m/s.
So,
54kmph = 54*5/18 = 15m/s.

The Length of platform = speed * time difference (because 20 is referral point)
= 15 * (36 - 20) = 240m.

Suraj said:   7 years ago
Here, it is solved by taking 15*20 but why?

20 is speed of man not a train. We are taking into account that speed of train. If we take the speed of train then answer will becomes zero.

Ravi Kumar said:   4 years ago
The length of platform = x + 300/36 = 15 m/s.

Can someone explain why we write the 15 m/s on R.H.S of the equation?

I really could not understand. If someone knows then please help me.
(5)

Mamtha said:   1 decade ago
The train pass the man 20sec, and the train pass a station 36sec.

So,36-20=16sec

Then we know that speed of the train of the train is 54km/hr.
=15m/sec

Therefore, 16*15=240m. Answer.


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