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?
120 m
240 m
300 m
None of these
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 17 of 28.

Nadeem said:   1 decade ago
In first row why second has been cancelled.

Austin said:   1 decade ago
Hello guys you can this problem in this way also.

Train Time = 36 second.

Men time = 20 second.

(36-20) = 16.

Speed = 54km/hr

54*5/18 = 15ms.

Distance = 15*16 = 240m.

Mohammed ali said:   1 decade ago
Hai friend I will put in another way you will sub higher to lower 36-20 you will get 16 answer and you can multiple:

16*54 = 864.

= 864*5/18.

= 4320/18.

= 240 answer.

Ajit said:   1 decade ago
First find out gap of time between train and man, then multiple train speed, then we got platform length.

Gap time = 36-20 = 16.

Then, train speed = 54*5/18 = 15 m/s.

Now, platform length = 16*15 = 240 m.

Premchandra saka said:   1 decade ago
First calculate length of both platform and train = (Train cross the platform)*Train speed in second = 36*(54*5/18) = 540 meter.

Then Train length = Speed in meter per second*Cross the man in second.

= 15 m/sec*20 sec = 300 meter.

Now, Platform length = Both platform and train length - Train length.

= 540 meter-300 meter.

= 240 meter.

SantiagoArg said:   1 decade ago
Who says the man is standing in the platform?

Swagath said:   1 decade ago
Thanks for sharing the useful information.

Paridhi said:   1 decade ago
Should we not consider the length of man? Why do we take it as a reference point?

Rasik said:   1 decade ago
Guys the total time to cross the platform is 36 sec with speed of 15 m/sec i.e. d=s*t.

36*15=540 m. Hence option is none of these.

Shubham Gupta said:   1 decade ago
s = d/ t.

Length of train = s*t = 15 m/sec*20 sec = 300 m.

Now let length of platform = x m.

Total length = (300+x) m.

s = d/t.

15 = 300+x/36.

x = 240 m answer.


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