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Comment by ez77 | Hacker News Reader

  In a country in which people only want boys, every family
  continues to have children until they have a boy. If they 
  have a girl, they have another child. If they have a boy,
  they stop. What is the proportion of boys to girls in the
  country?

Thoughts?

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A good analogy for this is flipping a coin. What is the proportion of total heads to total tails if a population of people each flip a coin until they get a heads. The answer is fairly trivial, as each coin flip is independent. Given a fair coin, you would expect the answer to be near 1. You could always calculate the variance given the population size using the binomial distribution.

A more fruitful question might be: what is the average family size in a country with these birthing habits?

Its been discussed on MathOverflow: http://mathoverflow.net/questions/17960/google-question-in-a...

If we assume there's an even chance of having a boy or girl, the proportion of boys to girls is still 50/50. It's basic stats. These are independent events.

Smart-ass, no-way-getting-an-offer answer: if we assume gender selection to be truly random, the answer may be anywhere between 0 and 1, period.

> the answer may be anywhere between 0 and 1

0 and infinity, actually.

(sorry, couldn't resist)

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