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Thread: Probability puzzle

  1. #1
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    Probability puzzle

    If you choose an answer to this question at random what is the chance you will be correct?


    A) 25%


    B) 50%


    C) 60%


    D) 25%
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  2. #2
    MHF Contributor
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    Re: Probability puzzle

    Spoiler:
    Pr[choose any letter] = 1/4

    Pr[Correct]=(Pr[Correct|choose a]+Pr[Correct|choose b] + Pr[Correct | choose c] + Pr[Correct | choose d]) x 1/4

    Pr[Correct] = (1/2 + 1/4 + 1/4 + 1/2) x 1/4 = 3/2 x 1/4 = 3/8

    Pr[Correct] = 3/8
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