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Math Help - Probability question - please help!?

  1. #1
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    Probability question - please help!?

    In a class of 20 pupils, 7 are left-handed and 13 are right-handed. Five pupils are selected at random from the class (the order is not important).

    Find the probability that the sample of 5 will include 2 or fewer who are left-handed.

    Thanks - please show me how you worked it out.
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  2. #2
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    Re: Probability question - please help!?

    Quote Originally Posted by neil12 View Post
    In a class of 20 pupils, 7 are left-handed and 13 are right-handed. Five pupils are selected at random from the class (the order is not important).

    Find the probability that the sample of 5 will include 2 or fewer who are left-handed.
    The probability of exactly two left-handed is \frac{\binom{7}{2}\binom{13}{3}}{\binom{20}{5}}.

    Now you finish.
    Thanks from neil12
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