Have you ever heard the brain teaser that goes something like this...
You have 12 coins, one of which is counterfit (either
lighter than or heavier than the others). Using a simple
balance scale you have but THREE weighings to determine
which is the counterfit AND whether it is heavier or
lighter! Well, it took me quite a while to solve that.
Recently while browsing through some old BYTE magazines I
came across a math column that dealt with this type of
program. I have included the listing "COIN.BAS" for your
enjoyment. Running it is self-explanatory. I highly
reccommend you read the accompanying article (see listing
for ref) as it is scientifically very interesting!