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Math Help - probability

  1. #1
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    probability

    Box 1 contains 5 red and 3 blue marbles while box 2 contains 2 red, 3 blue, and 1 white marble

    If you select box 2 and select a marble at random from it, then toss that marble into the other box and randomly draw a marble from it, what is the probability that the marble you draw is blue?
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  2. #2
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    Re: probability

    43.55 percent
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  3. #3
    Super Member ebaines's Avatar
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    Re: probability

    Quote Originally Posted by jsweston828 View Post
    43.55 percent
    Wrong.

    Suggest you approach it this way: Half the time the marble pulled from box 2 is blue, and half the time it's not. So half the time box 1 ends up with 4 out of 9 marbles that are blue, and half the time it ends up with just 3 out of 9 that are blue. So the probability of pulling a blue from box 1 is the average of 3/9 and 4/9.
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  4. #4
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    Re: probability

    Your answer isn't any of the options available!
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  5. #5
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    Re: probability

    Quote Originally Posted by jsweston828 View Post
    Your answer isn't any of the options available!
    \left( {\frac{3}{6}} \right)\left( {\frac{4}{9}} \right) + \left( {\frac{3}{6}} \right)\left( {\frac{3}{9}} \right) = ?
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  6. #6
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    Re: probability

    where did you get 3/6 from??
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