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June 11th, 2013, 11:19 PM   #1
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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
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June 12th, 2013, 08:34 AM   #2
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Re: Expected number of children

Hello, pavankumar.thati!

Quote:
In a world, every parent will stop giving birth after they find they have at least a boy and a girl.
Find 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.













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June 12th, 2013, 08:44 AM   #3
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Re: Expected number of children

This is just awesome yet very simple logic. Lots of thanks
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