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Math Help - finding possibilities when guessing answers

  1. #1
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    Unhappy finding possibilities when guessing answers

    Multiple choice questions each have 5 possible answers, one is correct. Assume that you guess the answers to 3 such questions. Using multiplication rule to find the probability that the first 2 guesses are wrong and the 3rd is correct. Find, P(WWC), where C is correct and W is wrong.
    This is a homework question that I am stumped on. If someone could at least send me in the right direction, I would be very grateful.
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  2. #2
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    Well if one out of 5 answers is correct, the odds of randomly guessing the correct answer are \frac{1}{5} and the odds of randomly guessing an incorrect answer are 1-\frac{1}{5}=\frac<br />
{4}{5}

    So use multiplication, the first two must be wrong so \frac{4}{5}*\frac{4}{5}=\frac{16}{25}

    But now we must multiply by something else because the third answer must be correct... you should be good from here
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