问一道数学

laixiangeffort · 发表于 2011-9-29 08:55:59

six cards numbered from 1 to 6 are placed in an empty bowl.First one card is drawn and then put back into the bowl;then a second one is drawn.if the card is drawn from random and if the sum of the numbers on the cards is 8,what is the probability that one of the two cards drawn numbered 5? A.1/6 B.1/5 C.1/3 D.2/5

laixiangeffort · 发表于 2011-9-29 08:58:47

有NN能帮下吗？

wyw1018 · 发表于 2011-9-29 09:27:22

答案D 共5中可能和为8，2/6，3/5，4/4，5/3，6/2，两种有5，概率2/5

laixiangeffort · 发表于 2011-9-29 10:24:30

问一道数学

所属分类: GMAT考试

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