Question

Two trains approach each other on parallel tracks. Each has a speed of 95 kph relative to the ground. If they are initially 8.5 km apart, how long will it be before they reach one another.
Explanation please!

Answer 1

Answer: 2.83 minutes

Explanation:

It is understood that trains are approaching. That is, they have speeds of equal magnitude but opposite. When train A travels x meters northbound, then train B travels the same distance southbound.

Therefore trains approach at a speed of:

$V = 95 +95 = 190\ km / h$

Then:

$V = \frac{x}{t}\\\\t = \frac{x}{V}$

Where x is the distance between the trains

$x = 8.5\ km$

So the time in which both trains meet is:

$t =\frac{8.5\ km}{180\ \frac{km}{h}}\\\\t=0.04722\ hours$

This is:

$0.04722*\frac{60\ minutes}{1\ hour} = 2.83\ minutes$

How long will it be before they reach one another ?

2.83 minutes