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RE: Brainteaser

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Turn on switch #1.
Wait 5 minutes.
Turn off switch #1 and turn on switch #2.
Go upstairs and look at the light.
If it's on, then switch #2 is the correct one.
If it's off, feel the bulb.  A warm bulb means it's switch #1, a cold
bulb means it's switch #3.

Mike Livingston, SE (and mostly lurker)

> -----Original Message-----
> From:	lsmith(--nospam--at) [SMTP:lsmith(--nospam--at)]
> Sent:	Friday, April 24, 1998 5:26 AM
> To:	seaoc(--nospam--at)
> Subject:	Brainteaser
> OK, this has nothing to do with engineering, but you do need to think
> to
> figure it out, so, I believe we all qualify.  According to a friend of
> mine, this was a question from a MENSA test:
> There is a switchplate with three (3) switches in the basement of a
> house.
> Up the stairs in a room on the ground floor is a light bulb.  The new
> owner
> of the house knows that the light bulb is controlled by one of the
> three
> switches and is in the basement.  With only one trip up the stairs,
> how can
> the new owner determine which switch controls the light bulb?