Aptitude - Problems on Trains - Discussion

Train moves with speed 125m/10 sec,.. So need to convert it as KM/ Hr ,..To convert 125m to KM we have to divide it with 1000 so it is 125/1000 and to convert 10 sec to hrs we have to divide it with 3600 so it is 10/3600.
Then it becomes (125/1000)Km/(10/3600)hr.
So we can change it to (125/1000)*(3600/10)..
It is (5/40)*(360) = (360*5)/40 = 180/4 = 45 Km/Hr.

.. Now we have got the speed in 1 Hour ie 45 Km..

As the man is travelling at 5 Km/Hr.. In that 1 Hr he already travelled 5 Km's.. So the train speed should be 45+5 Km's to cross that person in that 1 Hr.. Now answer is 50 Km/Hr.. I hope it is clear,... Take a paper a write exactly what i have given above,.. I am sure u guys will like it..

Can anyone find another way of solving this? Apart from relative speed?

How to relative 45 with man running speed. Please explain it any one.

This is good Question i understand that, some friend disturb for 18/5. its simple its unit for km/hr. let see that1km=1000m & 1hr = 3600 second so 1000/3600 = 5/18 . And see that If we want to small unit convert in to big unit we have to divide & if we want to big unit convert in to small we have to multiply so here they dividing and write 18/5 ok so encourage your self my friend go ahead. VIMAL SONI & DUSHYANT SONI

@Vasudeva reddy

1km = 1000m =100,000cm
1 inch = 2.54cm
1 ft=12 inches = (12*2.54)cm
1km = 0.621371192 mile
1.609344 km = 1 mile

Hi I can't understand friends. What is this x-5 ?

Please anyone explain clearly.

We need the speed of the train
we have only one clue about the train is 125m and 10s
speed=distance/time
(i.e)125/10= 12.5 m/s
but we need the answer in km/hr so convert it

12.5*(18/5)=12.5*3.6
=45 km/hr almost we got it
then about the direction, it is in same direction

Now the speed of the train as x,
because of same direction subtract it from x
x-5=45
x=45+5
x=50km/hr

Thanks frnd. I understand properly.

Nice explanation from you frnds but ravi said that we had add that relative speed, I can't understand from his point of view.

Very good explanation by Suganthan.