Aptitude - Problems on Trains - Discussion

Let the train A started at the end of other train B. So, it has to first cover the whole length of the train B and to completely cross B it has to cover additional length of the train A. So, length=2*lenth of each train.

Lets take it as train t1 speed=46*(5/18)=115/9 m/sec.
and similarly train t2's speed= 36*(5/18)=10m/sec.
Now after 36 sec t1 will cover=36*(115/9)=460m
and t2 will cover=36*10=360m
So the difference between their head engine will be=460-360=100m
So the length of trains will 100/2=50 each

Length of train is equal to diffence in speeds multiplied by that's all.

46-36=10km/hr.

36sec*10km/hr.

36*10* (5/18) mts/s.

100mts.

EASIEST WAY
(10*5/18)*36=100/2=50

Relative speed 46-36= 10 kmph
10 x 5/ 18 = 25/9
in 36 second total distance covered = 100m
100/2= 50 m length of each train.

We are supposed to find length of each train .
But both train are moving in same direction.
So let the length of each train be x respectively.
So the distace covered will be x+x=2x metres

For all those who got doubt why 46-36?
Its because both train are moving in same direction.
So as per the formula when moving in same direction.it should be subtracted.
When moving in opposite direction,it should be added.

Since the Trains are moving in the same direction The diff between their speeds has to be calculated.
46 kmph - 36 kmph = 10 kmph

convert into meters per second 10 x 1000 meters / 3600 seconds
We get 25/9.

Now apply formula distance = speed x time = 25/9 x 36
Cancelling 36 with 9 we get 4 multiply with 25 we get 100 meters, which is the length of two trains.
As per the question the two trains length is the same there fore each train length is 50 meters.

I can't get,please tell me, Why did we get 46-36? why didn't we get (46+36)

and why did we get 2x/36?

Please explain me.

How can we conclude that distance covered is 2x because here both the trains are moving and hence along with covering the distance 2x, they will cover some more distance. Please make this thing clear.