Re: [理工] [機率]-機率
※ 引述《AAJJBurnett (叫我投手)》之銘言：
: suppose that ther are 14 songs on a compact disk(CD) and you like 8
: of them. When using the random button selector on a CD player , each
: of the 14 songs is played once in a random order .Find the probability
: that among the first 2 songs that are played,
畫樹狀圖：
7
----- 喜歡第二首
13
/
8 /
喜歡第一首 -----
14 \
\
6
----- 不喜歡第二首
13
8
----- 喜歡第二首
13
/
6 /
不喜歡第一首 -----
14 \
\
5
----- 不喜歡第二首
13
: (a)You like both of them
= (8/14)(7/13) = 56/182 (30.77%)
: (b)You like neither of them
= (6/14)(5/13) = 30/182 (16.48%)
: (c)You like exactly one of them
= (8/14)(6/13) + (6/14)(8/13) = 48/182 + 48/182 = 96/182 (52.75%)
(Check加起來的機率和是一)
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※ 編輯: swon 來自: 114.32.231.74 (09/29 16:36)
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