Picking cards-Probability

[saurabh_batra]

Bill has small deck of 12 cards, made up of 2 suites of 6 cards each valued 1 to 6. Thus there are two cards in the deck with same value. He draws 4 cards one by one and looks for pair of cards that have same value. What is the probability that he gets
a) exactly one pair
b) exactly two pairs

[tim]

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