箱子有20个蓝色球,30黄球和50个红球.随机抽5个球抽了的球不会放回去.事件A5个球中刚好抽中1个黄球1个红球(letAbetheeventthatexactlyoneballisyellowandoneballisredamongthe5chosenballs)(a)求事
箱子有20个蓝色球,30黄球和50个红球.随机抽5个球抽了的球不会放回去.
事件A5个球中刚好抽中1个黄球1个红球
(letAbetheeventthatexactlyoneballisyellowandoneballisredamongthe5chosenballs)
(a)求事件A机率(3分)
(b)求在事件A下,至少抽中3个球是蓝色的几率
findtheprobabilityofeventagiventhatatleastthreechosenballareblue(4分)