Puzzle 1: P is prime...

Thread Starter

Dave

Joined Nov 17, 2003
6,960
I've not done this for a while so when I came across a couple of puzzles I immediately thought of you guys! I wasn't sure where to post this, but having looked at the puzzles these are very much mathematically focused so thought that the Math forum was the best place.

Ok, so puzzle 1:

Why is that if p is a prime number bigger than 3, then p^2-1 is always divisible by 24 with no remainder?

Dave
 

Thread Starter

Dave

Joined Nov 17, 2003
6,960
Dave,



This guy explains it as good as anyone can.

http://puzzles.nigelcoldwell.co.uk/fifteen.htm

Ratch
I know Nigel well; in fact many of the puzzles I am looking at are collated on his site.

For anyone wanting to attempt this puzzle (and other puzzles), don't go onto the above link (or Nigel's site) as it contains the answer(s). I will use Nigel's site for the actual answers when people have had a chance to do the puzzles.

Dave
 
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