Probability. NEED HELP!!!
posted by Tom on .
What is the probably that a fivecard hand dealt from a standard deck of cards will include four cards of the same alue? (This is called a "four of a kind" in poker)

figure out how many cards are in a deck {52} then take the number of cards in a deck and compare it to the numbers of cards in a four of a kind {4}

The number of possible ways to deal 5 cards from a standard deck is 52choose5 = 52!/5!(525)! where ! means factorial. This will be the denominator in your probablity calcuator.
Now for the numerator. There are 13 possible choices for your 4ofakind (A,2,3,..Q,K). That takes care of the 4ofakind part. Your hand still has one more card. There are 48 other cards. So, the number of ways to have 4ofakind in a 5card hand is 13*48. This is your numerator.