among a group of 2500 people,35%invest in municipal bonds,18%invest in oil stocks,and 7% invest in both .if 1%is to be randomly seleced from the 2500 people ,what is the probability that the person selected will be one who invest in municipal bonds not in oil stocks?
答案给的是7／25 说875投资政府债券 175两样都投 所以就有700直投政府债券 表示不明白啊
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发表于 2013-4-14 21:14:39
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