[Zeke]

Here's a little brain teaser from the Net. I don't know if it's proprietary to where I found it, but I'll let it remain anonymous for the time being unless I get flak.

"Brainteaser

You are working in a building and have a problem. On the top floor are three standing lights. On the ground floor are three switches, which control the lights, presently all in the "off position. You don't know which switch controls which light, except that there is a one-to-one correspondence. You're down on the ground floor and want to label the switches. But you want
to do it in as few trips up stairs as possible.


The room the lights are in can only be seen from the top floor (it has no windows and its at the end of a long corridor.) There's no one around to help. You must do it alone.

What is the fewest trips you can make to determine which switch turns on which light? You may assume that the bulbs have just been replaced, all the wiring is good, etc."

OK, here's how I thought I solved it.
" Turn on 2 lights, go upstairs and determine which of the 3 is not lit. Return to ground floor, label the appropriate switch and switch off 1 of the first 2. Back to upstairs to eliminate which one and you have it."

I got a response from the "author" that I got no prize.

Do me better then, One trip? I need to know how that works. NO trips? Well, color me stupid.