[計量] 請教一題計量

看板GRE作者 (豪瓜)時間14年前 (2010/08/13 20:17), 編輯推噓2(202)
留言4則, 4人參與, 最新討論串27/41 (看更多)
老方那發的 數學一題 If two numbers are to be selected from the first ten positve integers with replacement, what is the probability that at least one of them is even? A. 2/9 B. 1/4 C. 1/2 D. 3/4 E. 7/9 我覺得答案是E 可是答案給的是D 我的算法是 C(10,2)-C(5,2) 35 7 -----------------------= ----------- = ----- C(10,2) 45 9 -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 123.193.31.98

08/13 20:24, , 1F
with replacement! 1-0.5*0.5
08/13 20:24, 1F

08/13 20:25, , 2F
推樓上 正想打XD
08/13 20:25, 2F

08/13 20:38, , 3F
謝謝^^
08/13 20:38, 3F

08/13 20:58, , 4F
推一樓
08/13 20:58, 4F
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文章代碼(AID): #1CPJVjsq (GRE)