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题库 / GMATLA-PS-42
There are 8 magazines lying on a table; 4 are fashion magazines and the other 4 are sports magazines. If 3 magazines are to be selected at random from the 8 magazines, what is the probability that at least one of the fashion magazines will be selected?
~$\frac{1}{2}$~
~$\frac{2}{3}$~
~$\frac{32}{35}$~
~$\frac{11}{12}$~
~$\frac{13}{14}$~
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第一本是体育杂志的概率 4/8 第二本 3/7 第三本 2/6
故“3本全是体育杂志”的发生概率是 4/8*3/7*2/6=1/14
则其互斥事件发生的概率即为13/14
total： 8*7*6 / 3! =56
none: 4*4*2 / 3! = 4
at least one = 56-4 = 52
probability = 52/56 = 13/14
2. （4*3*2 ）/ （8*7*6）= 1/14， 1 - 1/14 = 13/14
我们并不了解｛Neither｝的学生数量，缺少条件无法计算