The Three Switches
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Downstairs in a house are three identical on-off switches. One of them controls the lamp in the attic. The puzzle is to work out which switch controls the lamp. The rules are as follows. You are allowed to manipulate the switches all you like, and then you are allowed a single trip to the attic. How do you do it? To clarify: When you are downstairs there is no way to see into the attic, or see reflected light from the attic. Once you have gone to the attic you are not allowed back to the switches. <edit>you can also assume original state of all switches to be off.</edit><hint>Otherwise it won't work</hint> Note: If you already know the answer, or reads the newspaper where I nicked the puzzle from, then please don’t write it up immediately in the comments! Give those who have never heard it before a chance to suffer, I mean enjoy finding the solution.
Wrong is evil and must be defeated. - Jeff Ello
Took me a couple minutes, but I remembered the answer... It's a nice warm-up problem... :)
Proud to have finally moved to the A-Ark. Which one are you in?
Author of the Guardians Saga (Sci-Fi/Fantasy novels) -
- Turn all the switches off;
- Go to the attic;
- Remove the bulb from the lamp;
The correct answer is now "none of them". :-D
"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer
Wouldn't work in this house: some of the switches are "top for off", others are "bottom for off"...:sigh: One of these days I'll sort it out, but I'm afraid the writing won't take changes and I don't want to have to redecorate... :laugh:
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Well spotted.
Wrong is evil and must be defeated. - Jeff Ello
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Wouldn't work in this house: some of the switches are "top for off", others are "bottom for off"...:sigh: One of these days I'll sort it out, but I'm afraid the writing won't take changes and I don't want to have to redecorate... :laugh:
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
Well, he didn't state top or bottom, he stated off. :)
Wrong is evil and must be defeated. - Jeff Ello
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Two ways I can think of: 1) Look at the effect of each switch on other lights in the house. The one that doesn't have any effect is the attic one (or a bulb is blown) 2) Send the wife up to the attic and tell her to yell when the light goes on!
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
Those are practical solutions, not adjusted for silly puzzles. My wife wouldn't go up to the attic in any case.
Wrong is evil and must be defeated. - Jeff Ello
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Those are practical solutions, not adjusted for silly puzzles. My wife wouldn't go up to the attic in any case.
Wrong is evil and must be defeated. - Jeff Ello
I'm a practical person! :laugh:
Jörgen Andersson wrote:
My wife wouldn't go up to the attic in any case.
Too many spiders? (Can't stand the venomous little buggers, myself)
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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Well, he didn't state top or bottom, he stated off. :)
Wrong is evil and must be defeated. - Jeff Ello
If you don't know what they control, you don't know which way is on... ;)
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
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I'm a practical person! :laugh:
Jörgen Andersson wrote:
My wife wouldn't go up to the attic in any case.
Too many spiders? (Can't stand the venomous little buggers, myself)
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
Mice traps, or rather the reason for them.
Wrong is evil and must be defeated. - Jeff Ello
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If you don't know what they control, you don't know which way is on... ;)
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
OriginalGriff wrote:
If you don't know what they control, you don't know which way is on
So if you know that they control a lamp in the attic... :doh:
Wrong is evil and must be defeated. - Jeff Ello
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Downstairs in a house are three identical on-off switches. One of them controls the lamp in the attic. The puzzle is to work out which switch controls the lamp. The rules are as follows. You are allowed to manipulate the switches all you like, and then you are allowed a single trip to the attic. How do you do it? To clarify: When you are downstairs there is no way to see into the attic, or see reflected light from the attic. Once you have gone to the attic you are not allowed back to the switches. <edit>you can also assume original state of all switches to be off.</edit><hint>Otherwise it won't work</hint> Note: If you already know the answer, or reads the newspaper where I nicked the puzzle from, then please don’t write it up immediately in the comments! Give those who have never heard it before a chance to suffer, I mean enjoy finding the solution.
Wrong is evil and must be defeated. - Jeff Ello
What's the purpose of going to the attic if you cannot go back to the switches afterward?
The difficult we do right away... ...the impossible takes slightly longer.
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Downstairs in a house are three identical on-off switches. One of them controls the lamp in the attic. The puzzle is to work out which switch controls the lamp. The rules are as follows. You are allowed to manipulate the switches all you like, and then you are allowed a single trip to the attic. How do you do it? To clarify: When you are downstairs there is no way to see into the attic, or see reflected light from the attic. Once you have gone to the attic you are not allowed back to the switches. <edit>you can also assume original state of all switches to be off.</edit><hint>Otherwise it won't work</hint> Note: If you already know the answer, or reads the newspaper where I nicked the puzzle from, then please don’t write it up immediately in the comments! Give those who have never heard it before a chance to suffer, I mean enjoy finding the solution.
Wrong is evil and must be defeated. - Jeff Ello
I send a drone to the attic with a camera so I can see which switch switches the light on.
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Downstairs in a house are three identical on-off switches. One of them controls the lamp in the attic. The puzzle is to work out which switch controls the lamp. The rules are as follows. You are allowed to manipulate the switches all you like, and then you are allowed a single trip to the attic. How do you do it? To clarify: When you are downstairs there is no way to see into the attic, or see reflected light from the attic. Once you have gone to the attic you are not allowed back to the switches. <edit>you can also assume original state of all switches to be off.</edit><hint>Otherwise it won't work</hint> Note: If you already know the answer, or reads the newspaper where I nicked the puzzle from, then please don’t write it up immediately in the comments! Give those who have never heard it before a chance to suffer, I mean enjoy finding the solution.
Wrong is evil and must be defeated. - Jeff Ello
The classic solution (which I won't give away) may not work too well with modern LED globes! CFLs maybe. Cheers, Peter
Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012
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Downstairs in a house are three identical on-off switches. One of them controls the lamp in the attic. The puzzle is to work out which switch controls the lamp. The rules are as follows. You are allowed to manipulate the switches all you like, and then you are allowed a single trip to the attic. How do you do it? To clarify: When you are downstairs there is no way to see into the attic, or see reflected light from the attic. Once you have gone to the attic you are not allowed back to the switches. <edit>you can also assume original state of all switches to be off.</edit><hint>Otherwise it won't work</hint> Note: If you already know the answer, or reads the newspaper where I nicked the puzzle from, then please don’t write it up immediately in the comments! Give those who have never heard it before a chance to suffer, I mean enjoy finding the solution.
Wrong is evil and must be defeated. - Jeff Ello
if the light is incandescent or halogen, it will get hot if left on. so switch on the first switch, and get distracted for 10 minutes, switch it off, switch on the next one and race upstairs. If the light is on, it is that 2nd switch. If it is off but hot, it was the first switch. Else it is the third switch. If it's an energy-efficient bulb, this won't work.
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Two ways I can think of: 1) Look at the effect of each switch on other lights in the house. The one that doesn't have any effect is the attic one (or a bulb is blown) 2) Send the wife up to the attic and tell her to yell when the light goes on!
Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...
OriginalGriff wrote:
Send the wife up to the attic and tell her to yell when the light goes on!
:thumbsup:
Once you lose your pride the rest is easy. In the end, only three things matter: how much you loved, how gently you lived, and how gracefully you let go of things not meant for you. – Buddha
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Those are practical solutions, not adjusted for silly puzzles. My wife wouldn't go up to the attic in any case.
Wrong is evil and must be defeated. - Jeff Ello
-
Downstairs in a house are three identical on-off switches. One of them controls the lamp in the attic. The puzzle is to work out which switch controls the lamp. The rules are as follows. You are allowed to manipulate the switches all you like, and then you are allowed a single trip to the attic. How do you do it? To clarify: When you are downstairs there is no way to see into the attic, or see reflected light from the attic. Once you have gone to the attic you are not allowed back to the switches. <edit>you can also assume original state of all switches to be off.</edit><hint>Otherwise it won't work</hint> Note: If you already know the answer, or reads the newspaper where I nicked the puzzle from, then please don’t write it up immediately in the comments! Give those who have never heard it before a chance to suffer, I mean enjoy finding the solution.
Wrong is evil and must be defeated. - Jeff Ello
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if the light is incandescent or halogen, it will get hot if left on. so switch on the first switch, and get distracted for 10 minutes, switch it off, switch on the next one and race upstairs. If the light is on, it is that 2nd switch. If it is off but hot, it was the first switch. Else it is the third switch. If it's an energy-efficient bulb, this won't work.
And we have a winner.
Wrong is evil and must be defeated. - Jeff Ello
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The classic solution (which I won't give away) may not work too well with modern LED globes! CFLs maybe. Cheers, Peter
Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012
Exactly what I thought, this "riddle" is going to die out...
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Downstairs in a house are three identical on-off switches. One of them controls the lamp in the attic. The puzzle is to work out which switch controls the lamp. The rules are as follows. You are allowed to manipulate the switches all you like, and then you are allowed a single trip to the attic. How do you do it? To clarify: When you are downstairs there is no way to see into the attic, or see reflected light from the attic. Once you have gone to the attic you are not allowed back to the switches. <edit>you can also assume original state of all switches to be off.</edit><hint>Otherwise it won't work</hint> Note: If you already know the answer, or reads the newspaper where I nicked the puzzle from, then please don’t write it up immediately in the comments! Give those who have never heard it before a chance to suffer, I mean enjoy finding the solution.
Wrong is evil and must be defeated. - Jeff Ello
-
The classic solution (which I won't give away) may not work too well with modern LED globes! CFLs maybe. Cheers, Peter
Software rusts. Simon Stephenson, ca 1994. So does this signature. me, 2012
