Show that the probability of scroing exactly n points is

[nowimpsbball]

Homework Statement

A player tosses a coin repeatedly. Heads is one point, tails is two points. A player tosses until his score equals or exceeds n. Show that the probability of scoring exactly n points is (2+(-1/2)^n)/3

Homework Equations

The Attempt at a Solution

My guess would be a proof by induction, but not really sure how to go about this or any attempted proof

Thanks

 

[NateTG]

Seems pretty straightforward to me. Why don't you start by doing the initial cases (n=1,2) and writing out the inductive step?