<PRE><B>Question 593109</B>
Suppose an opaque jar contains 5 red marbles and 10 green marbles. I experiment picking 2 marbles from the jar without replacing the first one. 
1. What is the probability of getting a green marble first and a red marble second?
Ans: (10/15)(5/14) = 50/210 = 5/21
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2. What is the probability of getting a green marble and a red marble? How is this different from question #1?
# of ways to succeed: 5*10 = 50
# of random pairs: 15C2 = 105
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P(red AND green) = 50/105 = 10/21
 
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Cheers,
Stan H.
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