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Blatherings

a riddle:
Previous | Next by ben 12 May, 2006 - 10:03 AM

I got this in an email today:

There are eight rooms, each with a single door to go in and out. Four of the rooms have light switches and four of them have light bulbs. You can enter and exit each room exactly one time. After you leave a room, the door closes and locks behind you. Your job is to determine which light switches control which light bulbs.




5/12/2006 >> muhgcee

1) Enter switch room 1. Turn switch on. Leave.
2) Enter switch room 2. Turn switch on. Wait 5 minutes. Turn switch off. Leave.
3) Enter switch room 3. Turn switch on. Leave immediately.

The bulb that is lit and hot corresponds with switch 1.
The bulb that is not lit and hot corresponds with switch 2.
The bulb that is lit and not hot corresponds with switch 3.
The bulb that is not lit and not hot corresponds with switch 4.


5/13/2006 >> ben

what if:

room 1 has been on the whole time and burns out just before you come in?


5/13/2006 >> muhgcee

why would that happen?


5/14/2006 >> ben

who knows... just not sure of all of the parameters, hehe


5/15/2006 >> rich

what if the light switches are not working? what if the light switches turn on more than one blub? what if the light switches really make the doors lock and unlock?

I mean if we are not sure of the parameters then anything is open. I think one must assume that light switches work like light switches normaly do and that light blubs are not burnt out as light bulbs are normaly not burnt out. Otherwise the riddle would be impossible.


5/15/2006 >> muhgcee

That is what I am thinking exactly.


5/15/2006 >> ben

i was just wondering how you guys would attack it... when i was looking around for more info about this, some people said that they were asked this during interviews, and the way people answered the riddle was important too




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