Place a coin with radius 3 on the table, and then place a coin with radius 1 touching it and above it. Roll the small coin without slipping all the way around the large coin, until it is above it again. How many revolutions does the small coin make? Andy On Sat, Nov 11, 2017 at 8:06 AM, James Propp <jamespropp@gmail.com> wrote:
Anyone have a favorite puzzle in which miscounting plays a role?
My favorite is the classic bookworm puzzle (see https://math.stackexchange.com/questions/1271651/how-is-this-true-bookworm-p... ).
Another example: A man was born in 50 BC and died on the same day in 50 AD. How old was he when he died?
I'm especially interested in puzzles that lend themselves to solvers committing fencepost errors, and off-by-one errors more generally.
Jim Propp _______________________________________________ math-fun mailing list math-fun@mailman.xmission.com https://mailman.xmission.com/cgi-bin/mailman/listinfo/math-fun
-- Andy.Latto@pobox.com