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SAT2 概率题
Three cards are drawn from an ordinary deck of 52 cards.Each card is replaced in the deck before the next card is drawn.What is the probability that at least one of the cards will be a spade?
求教思路和过程
人气:153 ℃ 时间:2020-05-21 12:37:49
解答
是不是37/64?答案是这个,请问具体是什么思路呢?要逆向思维,每次不是spade的几率是3/4,三次就是开三次方,最后用1减下就是答案了
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