A beetle starts at a point O on the floor. It walks 1m east, then 1/2m west, then 1/4m east and so on. How far it finish off O and how far did it actually walk?

Now here's my working:

We are given, ratio r = -(1/2), and first term a = 1 ... Since |r| < 1, it's a series that converges to a limit, so:

S = a / 1 - r

S = 1 / 1 - (-1/2) = 2/3

Therefore, the beetle ends up 2/3m from O.

Now ... I want help with how far did it actually walk. How should I go about calculating that?