From: Dan Asimov <dasimov@earthlink.net> To: math-fun <math-fun@mailman.xmission.com> Sent: Wed, July 7, 2010 3:41:04 PM Subject: [math-fun] Probability puzzle (This problem is said to be one that Google asked prospective employees in job interviews. My phrasing is almost identical to how it was presented to me.) PUZZLE: Suppose that in a very large population, each family has children until the first boy is born, and then has no more. What is the percentage of girls in the population? (Of course, make all the usual simplifying assumptions in this kind of problem.) --Dan ________________________________ Phooey, this isn't at all a mathematical puzzle. A social convention cannot override biology, so the proportion of boys and girls is the biologically determined one, nominally 1/2, 1/2. -- Gene