Aptitude - Problems on Trains - Discussion

So in the above problem let us consider that the speed of the person is 5 km\hr .

Leave the 5 as it is and then convert the km\hr into m\s
that means 1 km=1000m
and 60min=3600sec

Now when actually converted 3600\1000 that would give u the two zero gets cut and remains is 36\10 that would give u after dividing each by 2 i.e 18\5which means
(18m\5s)1.FRACTION

Now the major calculation,
Two object over here is Train and the Man consider them as A and B
where A is the Train as we have to find the speed of the train
then B is the speed of the Man is 5
so we get A-5

We had 125m the length of train time 10 seconds
already these are in meters and in seconds no need to convert them so 125m\10s u get (25m\2sec) 2.FRACTION

Now, finally get the first fraction and the second fraction together i.e (18\5)*(25\2)u get 45 as answer when u calculate
then A-5=45 ,when u move the negative -5 to this side of the equals too sign it converts to positive giving u A=45+5

i.e 50 so A=50 and A is the speed of train!!hope u'll understood!!take care!!

Answer in Another way :-

Speed = 5*18/5 = 18 km/hr
Time = 10 sec.
X + 125 / 10 = 18
X + 125 = 180
X = 180-125
X=55

Now, Speed = X-5
So , Speed = 55 - 5
Speed = 50 km/hr

To avoid confusion

Simple convert the trains speed for 1 hr - metres/seconds, 125m/10 sec. So 125 * 6 * 60 / 10 * 6 * 60 = 45000 mtrs/ 3600 . So to convert it, divide by 1000, its 45 kms/hr.

As the man running in the same direction at a speed of 5kms/hr add 45 + 5, if the person moves in opposite direction then subtract. Just logic guys

Hey the quesion is about the speed of the train. jjust bcoz aman runs... will the speed of the train increase...? a little help here pls...

As from the problem. two contrain have to remember
*If the man moving towards train. so that train pass the man faster then speed so add the distance.
*If not move towards train. The train pass the man late.so minus the distance

Good expl. frm Rahuul

Simple you can multiply 5*10.

5-a man running 5km/hr and the train reached in 10 seconds.

5*10=50km/hr.

When two things are running in the same direction or opposite direction then we say that motion is in relative between them. So at first we find the relative motion and then find the speed of train.

If someone want to find out speed of man that are given in the question.

Hi. Please tell me why x-5 ?

Thanks mr. Suganthan. Its really very nice to understand thanks:) ) ).