You need to make a set of five rods for a magic trick, with numbers on them ranging from 1 to 31 inclusive. Then you ask people to pick a number and show you only the top number of whatever rods it is on. From that you have to guess which number the person picked. This has to be done within a few seconds and isn't a matter of remembering what numbers are on them.

What numbers should be on each of the five rods?

(In reply to The top number? by Charlie)

Charlie, you wrote: "If the person tells you it's on no rods, it's 31, as the total is zero to be subtracted from 31."

This solution fails because the problem strongly implied that no number can be omitted from the rods, since the problem stated that "Then you ask people to pick a number and show you only the top number of whatever rods it is on." They don't apparently have the option of not showing at least one top number. The fact that Lewis highlighted the phrase "only the top number" indicates that this was probably a tricky aspect of the puzzle. The "top" number has to be "the number physically at the top of the rod", not "the number of greatest magnitude on the rod." But what do I know? I'm the guy who answered the "Egg-celent Question" puzzle with that "The yoke is on the previous posters" solution. I still have egg on my face over that one.
Edited on November 12, 2003, 3:04 am

Posted by Dan on 2003-11-12 02:58:35