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A new switches puzzle

In one room, we have three light switches.
In another room, we have three bare light bulbs.

Each switch controls one bulb in the "normal" way (up is on, down is off).

With a SINGLE trip to the switch room, followed by a SINGLE trip to the bulb room, how can we tell which switch controls which bulb??

BradC
Wednesday, June 15, 2005

Q: Do we start out in the switch room, or are we allowed to know the initial state of the bulbs?

tjk
Wednesday, June 15, 2005

Start in the switch room, with all switches off (if that matters).

BradC
Wednesday, June 15, 2005

For all off: Turn two on.  Wait an hour.  Turn one of those switches off.

Go to the bulb room.  Whatever is on, is controlled by the on switch.  The hot one is controlled by the switch you turned on and off.  The cool one is the one that stayed off.

That's probably BS, but its all I can think of at the moment.

tjk
Wednesday, June 15, 2005

Bingo!

Although I would think that 10 minutes would be sufficient. :)

BradC
Wednesday, June 15, 2005

Minor nit-pick, you might want to note that they are incandescent bulbs.  Not all lights produce heat (flourescent bulbs don't).

Lou
Thursday, June 16, 2005

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