Explanation

Let the speed of the slower friend be $x$ km/h, then the speed of the faster friend is$x+2$ km/h.

After 1 hour, their total distance apart is the sum of their speeds:

$$x+(x+2)=10$$

Simplifying:

2x+2=10

$$2x=8\Rightarrow$$x=4km/h

So, the slower friend's speed is 4 km/h, and the faster friend's speed is $4 + 2 = 6$ km/h.