→ miisoo :謝謝你 01/08 01:27
※ 引述《miisoo (味噌)》之銘言：
: (1)two cards are randomly selected from an ordinary playing deck.
: what is the probability that they form a blackjack?
: That is ,the probability that one of the cards is an ace
: and the other one either a ten, a jack, a queen,or a king.
: (2)compute the probability that a hand of 13 cards contains
: (a)the ace and king of some suit
: (b)all 4 of at least 1 of the 13 denominations.
: 算好久，還是解不出來> <"
: 請會的人幫忙解答，謝謝
: 答案(1)0.0483
: (2)a 0.2198
: b 0.0324
2a: 13張牌中有AK同花的機率
分子
4x(一組AK同花) -6x(兩組AK同花) +4x(三組AK同花) -1x(四組AK同花)
= 4xC(50,11) -6xC(48,9) +4xC(46,7) -C(44,5)
= 139565328072
分母
C(52,13)
= 635013559600
機率
0.219783225
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