Aptitude - Problems on Trains - Discussion

speed of the train 1 = 46km/hr,
speed of the train 2 = 36km/hr,
Relative speed = 46 - 36 = 10km/hr.
t = 36sec.

10 * 5/18 = 50/18 m/sec.
S = d/t.
S = L1 + L2.
Here two trains have equal lengths.
So, its 2L1.
S = 2L1/t.
50/18 = 2L1/36.
L1 = 50m.
So, the length of each train is 50 m.

The two trains were at race from the same point. One is not behind the other to cross 2x length, so it will be only x length.

Am I right?

It is correct 100m is the answer, but the trains are each length, the faster has to cross the slower train and the Faster train itself so, we divide it by 2 (2 trains).

To find the length of each train, you can use the relative speed formula:

Relative Speed = Speed of Faster Train - Speed of Slower Train.
Relative Speed = (46 km/hr - 36 km/hr) = 10 km/hr.
Now, you need to convert the relative speed to meters per second (m/s) because the time is given in seconds:
1 km/hr = 5/18 m/s.

So, 10 km/hr = (10 * 5/18) m/s = (50/18) m/s = (25/9) m/s (approximately)
Now, you can use the formula for distance:
Distance = Speed x Time.
Distance = (25/9) m/s x 36 seconds = (25/9) x 36 meters,
Distance = 100 meters (approximately).
Since the faster train passes the slower train in 36 seconds, the length of each train is 100 meters.

The answer should be 100.

It's a simple calculation, in the above question mention that is found out the length of each train.

Formula:
Length= speed ×time.
Speed = 46-36 = 10 ×5/18 = 2.7777.
Time = 36 seconds.

Then,
Length = 2.7777 × 36.
Length = 100 m.
Length of each train = 50m.

Since the length of the two trains are equal then in 36 seconds the trains cross each other.

Relative speed = 46 - 36 = 10kmph.
In 3600sec distance covered=10000m.
Therefore distance covered in 36 secs=10000/3600 * 36 = 100.
As the train covers each other and the length is of equal.
So the actual length of each train = 100/2 = 50m.

Speed = distance/time.
Speed = 2x/36 (2x assumed as distance covered by train and 36secs time is given).

The relative speed = 25/9 (calcuated in solution)

From both equation relative speed and speed should be same that's why;
2x/36 = 25/9.

I know most of us are not understanding how 2x/36 comes,

Here is my explanation;

Here 2x is the distance, then 36 is time in seconds.

Why we take 2x/36=25/9?

Can anyone please explain?