[extropy-chat] red and white zorfs again

[David]

spike wrote:
> 
> You have N red zorfs, N white zorfs and two large 
> identical urns.  You put all the zorfs into the 
> urns, in any combination you like, then leave the 
> room.  You ask a random person to enter the room, 
> choose one of the urns and bring it to you.  She
> shrieks and flees.  You then ask your spouse (with whom
> you are on more familiar terms) to bring you an urn.  
> You pull out one zorf without looking.  
> 
> Your goal is to pull a red zorf, these being your faves.
> 
> Question: how do you arrange the red and white zorfs
> in the urns such that you maximize the probability
> that you will get your red zorf?  Can you prove it?  How?
> 
> spike
> 
> 
> 
> 
> 
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Assuming all the zorfs must go in an urn :-)

You put one red zorf in one urn and all the white zorfs and
the rest of the red zorfs in the other.

Probability you will get a red zorf is (.50 + (N-1)/(2N))


Otherwise you put half the red zorfs in one urn, half in
the other and defenestrate the white ones.


-david