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

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Peter Scales

Posts: 192
From: Australia
Registered: 4/3/05
Re: Permutation problems
Posted: Aug 12, 2013 1:35 PM
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Hi Mark,

> The same fish/rat logic (inclusion/exclusion) needs
> to be applied to the second problem as well. For
> example, 9876450123 has been counted three times.
> I believe the solution is:
> 7!+8!+7! - (5!+4!+5!) + 2!

Thanks for picking up that double and triple counting.
I agree with your result.

Peter Scales.

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