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?
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:
276 comments Page 5 of 28.
Manikandan said:
5 years ago
From the given data, we can consider the only man as a reference point to find the length of train. So let us consider man is standing at the beginning, so 15*20 will be enough to find the length of the train, Am I right?
Jackiep said:
5 years ago
Time taken to pass a station = 36s.
Time taken to pass a man = 20s.
Difference=16s.
We have,
Distance = Speed X Time.
= 15 X 16.
= 240m.
Time taken to pass a man = 20s.
Difference=16s.
We have,
Distance = Speed X Time.
= 15 X 16.
= 240m.
(1)
Avinash Kapu said:
5 years ago
In this problem, it is considered that the man is standing at the extreme end. That's the reason length of the train is calculated as 15*20. What if the man is standing in the middle of the platform.
Tayek said:
5 years ago
Thanks @Satheesh.
VISHESH said:
5 years ago
Time taken by train to pass a station platform = 36 seconds.
Time taken by train to pass a man on platform = 20 seconds.
Speed of train = 54 km/hr.
= ( 54 * 5/18,
= 3 * 5,
= 15 m/s.
length of train = 15 *20.
= 300 m.
Let the length of train be x.
Then;
300 + x /36 = 15.
300 + x = 15*36,
x= 540 -300,
x =260.
So, length of the platform is 240m.
Time taken by train to pass a man on platform = 20 seconds.
Speed of train = 54 km/hr.
= ( 54 * 5/18,
= 3 * 5,
= 15 m/s.
length of train = 15 *20.
= 300 m.
Let the length of train be x.
Then;
300 + x /36 = 15.
300 + x = 15*36,
x= 540 -300,
x =260.
So, length of the platform is 240m.
Mansi said:
5 years ago
As the man is not moving and he can be ignored as a little particle because he has not such a big length (his standing distance) as a pillar.
So if we take the time of the train passes the man, we can get the exactly length of the train.
So there, the length of the train= (15*20).
If the man would have moving, there we can't take the same length.
We are not taking the time of the platform because it has a big length which can't be ignored.
So if we take the time of the train passes the man, we can get the exactly length of the train.
So there, the length of the train= (15*20).
If the man would have moving, there we can't take the same length.
We are not taking the time of the platform because it has a big length which can't be ignored.
Kavya said:
5 years ago
Why we have to multiple 15*20?
Syed zubair said:
5 years ago
Just subtract the time taken by train to pass a man with the time taken by a train to pass a station i.e 36-20 = 16.
16*15(speed in meters) = 240 meters.
16*15(speed in meters) = 240 meters.
Sahil shaikh said:
5 years ago
The train passes a station 36.
Man on platform 20.
Loss of time man 36-20=16.
Speed = distance/time.
15m/sec = L/16.
15x16 = 240 m.
Man on platform 20.
Loss of time man 36-20=16.
Speed = distance/time.
15m/sec = L/16.
15x16 = 240 m.
Murali krishna star said:
5 years ago
Length of the train relative to the station is 36*15=540,
Length of the train relative to man@20sec is
20*15=300.
Now,
Length of the train relative to station subtract the length of man 540-300=240.
Length of the train relative to man@20sec is
20*15=300.
Now,
Length of the train relative to station subtract the length of man 540-300=240.
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