Aptitude - Problems on Trains - Discussion

Thank you all guys I got many ideas.

Everything is ok and easy explanation.

But one thing is questionable.

If the train is crossing a man who is running in the same direction with a speed of 5km/hr, than than how the distance travelled in 10 secs is equal to the length of the train. Don't you think dear friends the distance travelled by the man should also be added to the length of the train.

Thanks for all related answer its easier for me too solve query like this.

18/5 divided because the conversion of m/sec to km/hr.

Solution: The train length is 125 m.

One man speed is 5 km/h. Time is 10 s.

The velocity of man with respect to train is v=distance/time.

125 m/10 s = 12.5 m/s.

We convert into km/h we multiplied with 18/5.

Then s = 12.5*18/5 = 45 km/h.

The train speed is 45+5 = 50 km/h.

What is the meaning of relative speed and also meaning of x-45=5?

Why it is subtracted by 5?

HEY NEERAJA.

Distance = Time*Speed 125 = 10*Speed.

Distance/Time = Speed 125/10 = (25/2) m/s = Speed.

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Answer should be in km/hr so convert m/s.

Km = 1000 m and hr = 3600 s.

M = km/1000 and s = hr/3600.

M/s = (3600/1000) km/hr.

M/s = (18/5) km/hr.

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The condition was speed = (25/2) m/s.

= (25/2)(18/5) km/hr.

= 45 km/hr.

The speed was relative to man so we have taken time in consideration of man.

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See further in in view answer.

I have a doubt were in some case we consider 18/5 and in some case we consider 5/18?

Can anyone please let me know in which of the cases we consider what?

To convert kilo meter/hour to meter/sec we consider 5/18.

To convert meter/sec to kilometer/hour we consider 18/5.