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Homework Help: Show that the probability of scroing exactly n points is

  1. Feb 11, 2008 #1
    1. The problem statement, all variables and given/known data
    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

    2. Relevant equations

    3. 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

  2. jcsd
  3. Feb 11, 2008 #2


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