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Math Help - omg probability is so hard!! =[[

  1. #1
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    Exclamation omg probability is so hard!! =[[

    can u show me how to do this step by step?








    Jerry has a CD case that contains 4 country music CDs, 1 rock-and-roll CD, 2 rap CDs, and 3 Tejano CDs. What is the probability of Jerry randomly selecting a Tejano CD and then, without replacing it, randomly selecting a rap CD from his case? A

    B

    C

    D
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  2. #2
    Rhymes with Orange Chris L T521's Avatar
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    Quote Originally Posted by whatxxever_2009 View Post
    can u show me how to do this step by step?








    Jerry has a CD case that contains 4 country music CDs, 1 rock-and-roll CD, 2 rap CDs, and 3 Tejano CDs. What is the probability of Jerry randomly selecting a Tejano CD and then, without replacing it, randomly selecting a rap CD from his case? A

    B

    C

    D
    The probability of drawing a Tejano CD is as follows:

    There are 3 Tejano CDs, but we have 4+1+2+3=10 CDs total. So the probability of him picking a Tejano CD first would be \frac{3}{10}. If he then picks a Rap CD without replacement, then the total number of possible CDs drops down to 9. Thus, the probability of him drawing a Rap CD after he draws a Tejano CD is \frac{3}{10}\cdot\frac{2}{9}=\boxed{\frac{1}{15}}

    Does this make a little more sense now? If you're still lost, please post back.

    Note that I moved your thread from the Geometry forum to the Probability and Stats forum.
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  3. #3
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    oh ok. but why do u have to multiply them together? whenever i have a problem like this will i always have to multiply them?
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