360.Another Matching Pair
★★★classical probabilityCh. 1 — Classical Probability and Combinatorics444+ Problems in Probability
Marissa has a deck of 40 cards: four 1's, four 2's, ..., four 10's. A matching pair (2 cards of the same number) is removed from the deck. If Marissa randomly draws 2 more cards, what is the probability that she draws another matching pair?
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After the removal, one rank has 2 cards left and nine ranks still have 4. Count matching pairs in the 38 remaining cards.
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