[extropy-chat] red and white zorfs again

[spike]

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