|
 It is a long time
ago now that I was first introduced to the Twelve Billiard Balls
problem. After weeks of struggle I thought I’d cracked it, but I
omitted to record my solution. Not that it’s simple to express your
solution clearly, as I recently found when I revisited it. Solving it
was easier, but it was still a chore to document it intelligibly.
So here’s a
holiday task for you.
Solve it, if you
haven’t already, then try your hand at laying out the solution so that’s
it’s easily understandable, and expedite it to Bikwil. But don’t
cheat and copy the method from a Gardner or de Bono book (or anywhere
else, for that matter). Your own words, please.
This is how it
goes:
There
are twelve billiard balls, all the same size and colour. They all weigh
the same with the exception of one which is slightly lighter or heavier,
but not noticeably so in the hand.
Your
challenge is to discover the odd ball and whether it is lighter or
heavier. You must use a beam balance only, and you are restricted to three
weighing operations.
The
clearest correct solution will be printed in Bikwil, in the March
1998 issue (No. 6). No fabulous prize for you, however, just the quiet
inner radiance of nonchalant, suave self-satisfaction.
Merry Christmas
to everyone. Especially to any readers in ill-health.
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