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:
277 comments Page 22 of 28.
Vaibhav said said:
8 years ago
Please explain in detail that divide factor.
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.
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.
Dharmendra (dj) said:
8 years ago
As we know,
A train passes a station platform in 36 seconds and man standing on the platform in 20 second.
We have speed of train is 15m/s,
So,
We know a man standing and train crossing platform
36-20=16 sec
Now we have actual time
Then distance= Time x speed
X. = 16x15 m/s
X= 240 m
Distance=240m.
A train passes a station platform in 36 seconds and man standing on the platform in 20 second.
We have speed of train is 15m/s,
So,
We know a man standing and train crossing platform
36-20=16 sec
Now we have actual time
Then distance= Time x speed
X. = 16x15 m/s
X= 240 m
Distance=240m.
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.
Varad shinde said:
8 years ago
He guys,
In the problem, there is a common formula used from the examiner is,
Distance = Speed x Time.
In the problem, there is a common formula used from the examiner is,
Distance = Speed x Time.
Satish said:
8 years ago
Let distance be x m.
Time take for crossing platform=36sec.
For a man on the same platform=20 sec.
Speed=D/T, we get speed of train=54*5/18=15m/sec.
Since the man is on the same platform we can subtract the time from entire time=36-20=16
So, S=D/T
15=x/16.
Then, x=15*16=240m.
That's all.
Time take for crossing platform=36sec.
For a man on the same platform=20 sec.
Speed=D/T, we get speed of train=54*5/18=15m/sec.
Since the man is on the same platform we can subtract the time from entire time=36-20=16
So, S=D/T
15=x/16.
Then, x=15*16=240m.
That's all.
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