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Topic: Permutation problems
Replies: 13   Last Post: Aug 12, 2013 2:23 PM

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Mahesh

Posts: 5
From: India
Registered: 3/2/12
Re: RE: Permutation problems
Posted: May 19, 2012 2:35 AM
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I could make some progress after your reply. I thought of doing it other way round. So now the sets are:
A: Contain fish |A|=23!
B: Contain rat |B|=24!
C: Contain bird |C|=23!
A n B: 21!
A n C: 20!
B n C: 21!
A n B n C: 18!

A' n B' n C'= Total permutations - (A u B u C)
= 26!-(23! + 24! + 23! - 21! - 20! - 21! +18!)
=4.0261.... * 10 ^ 26
Let me know if this is correct.
Thank you.



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