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:
279 comments Page 20 of 28.
Jinita said:
1 decade ago
Why took 15*20? and the method (36-20) i.e. taking difference can be applicable?
Reshmi said:
1 decade ago
I have the same doubt & Its not clear from all these explanations. Why you took 15*20 as the distance value?
Amol said:
1 decade ago
Friends I think time req. To cross man (20) is less than time req. To cross station (36). So length of station is more than length of train.
So,
Total length of station = 20sec*15m/sec + 16sec*15m/sec.
= lth of train + remaining lth of platform.
For 16 sec,
= 300+240.
= 540m.
So,
Total length of station = 20sec*15m/sec + 16sec*15m/sec.
= lth of train + remaining lth of platform.
For 16 sec,
= 300+240.
= 540m.
Srikanth said:
1 decade ago
Speed=54*(5/18)=15m/s.
Now time = 36-20=16.
Now distance(i.e length)=speed*time
=15*16
=240m/s.
Now time = 36-20=16.
Now distance(i.e length)=speed*time
=15*16
=240m/s.
Suresh said:
1 decade ago
First we are calculate the length of train compared with a man standing on the platform.
= (15*20) m.
=300m.
Second we are calculate the length of train compared with they passes a station platform.
= (15*36) m.
=540m.
We wanted to the length of platform X.
So, the length of platform X and the length of train compared with a man standing on the platform equal to the length of the train compared with they passes a station platform.
X+300m=540m.
X= (540-300) m.
=240m.
We were got the length of platform 240m.
= (15*20) m.
=300m.
Second we are calculate the length of train compared with they passes a station platform.
= (15*36) m.
=540m.
We wanted to the length of platform X.
So, the length of platform X and the length of train compared with a man standing on the platform equal to the length of the train compared with they passes a station platform.
X+300m=540m.
X= (540-300) m.
=240m.
We were got the length of platform 240m.
Shoeb said:
1 decade ago
Distance=Time*Speed.
* 54 x 5/18 = 15
* 15 x 20(given) = 300
* x+300/36=15
=240m
OR
* Distance = speed*time
* Distance = (54*5/18)*(36-20)
= 15*16
= 240
Speed , Time is given to us. We have to only apply the formula in proper way.
* 54 x 5/18 = 15
* 15 x 20(given) = 300
* x+300/36=15
=240m
OR
* Distance = speed*time
* Distance = (54*5/18)*(36-20)
= 15*16
= 240
Speed , Time is given to us. We have to only apply the formula in proper way.
Praveen R said:
1 decade ago
Time taken for reach the platform=36sec.
Time taken for reach a man= 16sec.
Speed (S) = (54*5) /18=15.
Distance between=36-20=16.
Then the distance=16*15.
=240.
Time taken for reach a man= 16sec.
Speed (S) = (54*5) /18=15.
Distance between=36-20=16.
Then the distance=16*15.
=240.
Shantanu said:
1 decade ago
Why x and 300m are added?
Sangram said:
1 decade ago
In simple process,
Bs-------------------m------------Be
A--------20S---------B------16S---C
l---------------36s---------------l
If man was reference point then T.P=36-20=16s.
We know length=speed*time.
Then lenth of train=(54*5/18)*16=15m/s.*16s.=240m.
Answer=240m.
Bs-------------------m------------Be
A--------20S---------B------16S---C
l---------------36s---------------l
If man was reference point then T.P=36-20=16s.
We know length=speed*time.
Then lenth of train=(54*5/18)*16=15m/s.*16s.=240m.
Answer=240m.
M.Ramya Devi said:
1 decade ago
Speed of the train=54km/hr.
Speed=54*5/18=15.
Train passes a station platform:Length=speed*time.
=15*36=540.
Train passes the man standing on the platform:Length=speed*time.
=15*20=300.
Length of the platform=540-300=240m.
Speed=54*5/18=15.
Train passes a station platform:Length=speed*time.
=15*36=540.
Train passes the man standing on the platform:Length=speed*time.
=15*20=300.
Length of the platform=540-300=240m.
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