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(2008年浙江理科19题)一个袋中装有若干个大小相同的黑球、白球和红球.已知从袋中任意摸出一个球,得到黑球的概率是2/5,从袋中任意摸出两个球,至少得到一个白球的概率是
(2008 Zhejiang Science Question 19) A bag contains a number of black balls, white balls and red balls of the same size. It is known that one ball is drawn from the bag and the probability of obtaining a black ball is 2/5. The probability of arbitrarily finding two balls and getting at least one white ball is