🚀 go-pugleaf

The difficulty in this problem is that you can't apply Bayes' theorem without
knowing the prior probability that, if your friend has a boy and a girl, the
girl is the one that you meet.  Half of the people have been arguing that the
probability is 50% because it's equally likely that you'll meet either child.
The other half have been arguing (wrongly, I think) that the probability is
100% because you did meet the girl.  But probability is not about single
events.  Probability answers the question, "If I saw my friend with one of
her children a large number of times, about how many of those times would
the child with her be female?"  I don't think it's necessarily correct to
assume that your friend would be equally likely to meet you with her son
as with her daughter, so the 50% camp is also on shaky ground.

-- 
John Dalbec (dalbec@cs.cornell.edu) Speak for yourself--I do!