Maya問: Play Cards 問題 ?

Question

1 套 52 張的 Play Cards , - 啤 牌 -

Question : 要 Random 抽 2隻， 其中 1隻 是 -紅心 A-及 任何 1 隻 K ，

Black Jack 機會是 多少 ?

Answer 1

1隻是紅心A及任何1隻K:

P=(1C1)X(4C1)/(52C2)

Black Jack:

P=(4C1)X(16C1)/(52C2)

Answer 2

P(其中一隻是紅心A及任何1隻k)=P(1st 紅心A and 2nd K) + P(1st K and 2nd 紅心A)
=2 x 1/52x4/51 = 4/1275

P(Black Jack)= P(1st is A and 2nd is a card of 10 or above) + P(1st is a card of 10 or above and 2nd is A)
= (4/52)x(16/51) + (16/52)(4/51) = (2x4x16)/(51x52) =64/1275