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A veterinarian has 5 dogs and 4 cats available for adoption. Four of the dogs are brown and 1 is gray.Three of the cats are browm and 1 is gray. Jena selects two animals at random. Find the probability that at least 1 is a cat given that at least 1 is gray.

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What are your thoughts on the question? –  Did Sep 26 '12 at 14:22

1 Answer 1

If I understood correctly we have to have 1 cat and 1 animal has to be gray. Lets count good possibilities p.

  1. We take gray cat. p = 8 (any animal other then gray cat)
  2. We do not take gray cat. So at least one has to be cat and we have to take the gray dog. So there is p = 3 (we have gray dog, we have to choose one brown cat, the gray cat is counted in option 1)

These two options are distinct. So all good p = 11 and the probability is 11/72

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Although the answer misses the mark ("given that" indicates conditional probability), I upvoted it because this is about as much as the OP deserves. –  user31373 Sep 27 '12 at 4:05

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