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 18 of 28.
Uvesh said:
8 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.
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.
Imran said:
8 years ago
Thanks @Satheesh.
Bhaskar said:
8 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.
=54*5/18*20= 300 and that is the length of the train.
Manikandan said:
8 years ago
According to me, it should be what is the length of the platform from the point man standing for the answer to be 240. Otherwise, the answer is 540.
Please correct me if I am wrong.
Please correct me if I am wrong.
Vaibhav said said:
8 years ago
Please explain in detail that divide factor.
ASIFAS HASPURA said:
8 years ago
@Vetri & @Sara both are correct.
A.m.manojkumar said:
8 years ago
Consider the man standing starting edge of platform. The train passes him in 20 sec means, we can measure the length of the train.
So, length of the train is,
(54km/3600sec)*20sec=300m.
Now train passed him,
Train =============>
Platform ########
Man $
From the above graph, 300m length train crossed him in 20 sec. Remaining 16sec train takes to cross the platform.
So,
Length of the platform is,
(300m/20sec)*16sec=240m.
So, length of the train is,
(54km/3600sec)*20sec=300m.
Now train passed him,
Train =============>
Platform ########
Man $
From the above graph, 300m length train crossed him in 20 sec. Remaining 16sec train takes to cross the platform.
So,
Length of the platform is,
(300m/20sec)*16sec=240m.
Rabiul said:
8 years ago
What is the relation between 'standing a man 20 sec''' and 'train length''?
Zainab said:
8 years ago
@Frank.
Good explanation.
Good explanation.
Siddhant ojha said:
8 years ago
Better approach would be.
15*36=540 which is the overall distance covered and then subtracting the length of the train form it.
Which is 15 * 20=300.
So, 540-300=240.
In this case, you will not need to solve the equation for x.
15*36=540 which is the overall distance covered and then subtracting the length of the train form it.
Which is 15 * 20=300.
So, 540-300=240.
In this case, you will not need to solve the equation for x.
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers