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Math Help - picking 2 defective question I cant understand answer

  1. #1
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    picking 2 defective question I cant understand answer

    Hello

    The question is:
    In a shipment of 100 televisions, 6 are defective. If a person buys two televisions from that shipment, what is the probability that both are defective?

    I calculated 6/100 * 6/100 = 9/2500 but the correct answer is 1/330. how do you arrive at 1/330?

    Angus
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  2. #2
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    Quote Originally Posted by angypangy View Post
    In a shipment of 100 televisions, 6 are defective. If a person buys two televisions from that shipment, what is the probability that both are defective?
    I calculated 6/100 * 6/100 = 9/2500 but the correct answer is 1/330. how do you arrive at 1/330?
    It should be \frac{6}{100}\frac{5}{99}
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  3. #3
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    Ah of course. Thanks. I was forgetting that it would be conditional prob.
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