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June 11th, 2013, 11:19 PM  #1 
Newbie Joined: Jul 2008 Posts: 7 Thanks: 0  Expected number of children
Hi all, I want to find the answer to the below question ? Q1. In a world, every parent will stop giving birth after they find they have atleast a boy and a girl. Now find what is the expected number of boys and girls in that world? Pr(Boy) = 1/2, Pr(Girl) = 1/2, getting boys and girls are mutually independent. I worked out the answer for this question But i got '2'. But the correct answer is '3'. Please give me the answer with an explanation Thanks in advance Pavan kumar 
June 12th, 2013, 08:34 AM  #2  
Math Team Joined: Dec 2006 From: Lexington, MA Posts: 3,267 Thanks: 407  Re: Expected number of children Hello, pavankumar.thati! Quote:
 
June 12th, 2013, 08:44 AM  #3 
Newbie Joined: Jul 2008 Posts: 7 Thanks: 0  Re: Expected number of children
This is just awesome yet very simple logic. Lots of thanks 

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