送交者: Amsel 于 2008-07-31, 23:14:45:
回答: 这个问题还真的在维基百科上 (Boy or Girl paradox) 由 HunHunSheng 于 2008-07-31, 23:08:11:
So P(two boys|twice boys) = P(two boys) * P(twice boy|two boys)/(0.25*( P(twice boy|two boys) + P(twice boy|(older girl and younger boy)) + P(twice boy|(older boy and younger girl)))) = 1/3.