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 23 of 28.
Dheeraj said:
1 decade ago
Can some tell me which formula we are applying for for
x+300
-----=15
36
I understood that once we multiply 15 and 36 we will get 540......
But, why we are multiplying them......?
Is it because of distance = speed * Time.....???
Explain me please???
x+300
-----=15
36
I understood that once we multiply 15 and 36 we will get 540......
But, why we are multiplying them......?
Is it because of distance = speed * Time.....???
Explain me please???
Aasif Javed said:
1 decade ago
@Ashwini is your calculation right?
Please check it.
x = 54*5/18*36 = 540m not 240m
Please check it.
x = 54*5/18*36 = 540m not 240m
Ashwini Shet said:
1 decade ago
Is it necessary to calculate the length of the train?
We can do it directly as:
distance = speed * time
Let x be the length of the platform , which train crosses in 36s.
x = 54 *5/18 *36 = 240m
We can do it directly as:
distance = speed * time
Let x be the length of the platform , which train crosses in 36s.
x = 54 *5/18 *36 = 240m
Nusrath Kamal said:
1 decade ago
Why you all are complicating this simple question, here how this work:
Answer = Length of the Train - Length of the platform
Length of the Train= Speed + Time (please refer the formula).
: 54 * 5/18 = 15(speed of the train)X 20 Time = 300
Length of the Platmform= Speed + Time
: 54 * 5/18 = 15 (Speed of the Train) X 36 Time = 540
So answer = 540 - 300 = 240 M
Answer = Length of the Train - Length of the platform
Length of the Train= Speed + Time (please refer the formula).
: 54 * 5/18 = 15(speed of the train)X 20 Time = 300
Length of the Platmform= Speed + Time
: 54 * 5/18 = 15 (Speed of the Train) X 36 Time = 540
So answer = 540 - 300 = 240 M
Satheesh.m said:
1 decade ago
Speed as we calculated 15m/sec
The difference from the ref pt (i.e.,man) to the train pass the platform is 16
So, 15*16=240m
The difference from the ref pt (i.e.,man) to the train pass the platform is 16
So, 15*16=240m
Pawan said:
1 decade ago
It is longest but easy to undertand
len = speed*time
speed: 54*5/18=15
Now calculate the length of train,
len=15*20
=300
now calculate the length of platform
use same formula (x=platform length)
300+x=15*36
x=540-300
x=240
len = speed*time
speed: 54*5/18=15
Now calculate the length of train,
len=15*20
=300
now calculate the length of platform
use same formula (x=platform length)
300+x=15*36
x=540-300
x=240
Manonmani said:
1 decade ago
I also having doubt.
Why we took 20 sec (300=20*15).
Instead of 30sec (450=30*15).
Why we took 20 sec (300=20*15).
Instead of 30sec (450=30*15).
Tara said:
1 decade ago
The above answer can be solved by Jagadeesh & Verti given method, i thinkg its also rite.
Sanjay punj said:
1 decade ago
Thanks sachin kamble.
Vivek said:
1 decade ago
Why we have multiplied with 20 means ... we have to take any one of the reference point. 36sec is train PASSES a station platform so we cant take. but here we can take it because man STANDING on the platform in 20 seconds. STANDING POINT is take it as reference point for calculating lengh of train.
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