SOLUTION: An urn contains 9 red balls and 6 yellow balls. If Tim chooses 6 balls at random from the urn, what is the probability that he will select 4 red balls and 2 yellow balls? Round you

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Question 799560: An urn contains 9 red balls and 6 yellow balls. If Tim chooses 6 balls at random from the urn, what is the probability that he will select 4 red balls and 2 yellow balls? Round your answer to decimal places.
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
An urn contains 9 red balls and 6 yellow balls. If Tim chooses 6 balls at random from the urn, what is the probability that he will select 4 red balls and 2 yellow balls? Round your answer to decimal places.
               Number of ways Tim can choose 4 reds any 2 yellows
Probability =  --------------------------------------------------
                   Number of ways Tim can choose ANY 6 balls


To get the numerator:

He can choose the 4 reds any of C(9,4) = 126 ways
For each of those 126 ways he can choose the 4 reds,
he can choose the 2 yellows in any of C(6,2) = 15 ways.
So that's 126×15 or 1890 ways.

To get the denominator:

There are a total of 9+6 = 15 balls
He can choose 6 in any of C(15,6) = 5005

               1890                           54
Probability = ------ which reduces by 35 to ----- = 0.377622377622377622...
               5005                          143

Round to however decimal places you were told to round it.

Edwin