Date: Dec 2, 2012 10:47 PM
Author: William Elliot
Subject: Re: No Putnam spoilers please
On Sat, 1 Dec 2012, William Elliot wrote:

> On Sat, 2 Dec 2012, Bart Goddard wrote:

> > William Elliot <marsh@panix.com> wrote in

> >

> > > How do we know if a question is a Putnam question?

> >

> > It'll have the number 2012 in it somewhere.

>

> "What's 5^2012 mod 7?" is a Putnam question? ;-}

>

What the heck, just to add some math, I'll solve it,

Putnam question or not.

phi(7) = 6; 5^2012 = 5^(6 * 335 + 2) = 5^2 = 25 = 4 (mod 7)

1800

180

30