Aptitude - Problems on Trains - Discussion

3600sec then, 1sec = 1/3600hr.
1km =1000m then, 1m = 1/1000km.
So,
km/hr to m/s is : 1/1000km bigger divided by 1/3600hr.
So, they put 18/5.

@Hemanth sairam.

Why 60 mins and 60 seconds taken there?

Please explain me.

How it 18÷5 will become? Please explain.

Here is the solution for this question:

The length of a train is given as 125m (here it is mentioned as m/s), and the speed is given as 5km/hr (here it is mentioned as km/hr).

While converting km/hr into m/s, we are multiplying the speed by 5/18; therefore while converting m/s into km/hr, we have to take the reciprocal of 5/18, that is 18/5. The speed of the train should be calculated in km/hr; therefore, we take 18/5.

How - 5 came? Please explain this step.

How this 18/5 come? please explain to me.

How 18/5 came after 25/2? Please answer.

18/5 is the direct formula to convert the m/seconds to km/hr.

In this given problem, we can convert the m/sec to km/hr so we use 18/5.

This is the concept of reference of frame.

Train speed is (x)
Let's say A person in a train says that a man(outside of the train(or) beside of train running at a speed of 5 km/ hr) running slow as (x-5)km/hr.

This means if the train speed is 20 km/hr. Then the man's relative speed is as slow as 15 km/hr when compared to train speed.
This relation is mentioned in the mathematical formula as( x-5)km/hr or ( example:20-5 km/hr).
So, the relative speed is;
X - 5 = (120/10)*(18/5)
So x = 50 km/ hr.
*18/5 is used to convert m/s into km/ hr.

I am not getting this. Anyone, help me to understand this.

Suppose we have to convert km/hour into m/s.
km/hour = 1000m/hour
i hour = 3600s
km/s = 1000m/3600s = 5/18.

Just reverse it, m/s into km/hour = 18/5, it's an easy way.