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#gre数教#

标题起源:GRE模仿测验APP-雷哥GRE

模拟考试卒网:https://gre.viplgw.cn/

A box contains 4 red chips and 2 blue chips. If two chips are selected at random without replacement, what is the probability that the chips are different colors?

A.1/2

B.8/15

C.7/12

D.2/3

E.7/10

剖析:两种色彩各选出一个的组合有C(4,1)*C(2,1),随机选出2个的总组开数是C(6,2),以是几率是P=C(4,1)*C(2,1)/C(6,2)=8/15