The Three Switches
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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
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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
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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
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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
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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
Firstly turn on switch1 for 1 minute, after 1 minute turn off the switch1, then turn on the switch2. go to the room and check the cases: case1: If bulb is on then switch2 is default switch. case2: Touch bulb by your hand if it is warm then switch1 is default switch. case3: If bulb is cold/normal then switch3 is default switch. default: No switch is working. ;)
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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
CFLs still get hot enough to the touch that you don't want to replace them immediately after they fail. LED's are only marginally more efficient; half of the "bulb" ends up being a heat sink. Bean counters being what they are; I'd expect it to be the bare minimum size required and to still get nice and warm.
Did you ever see history portrayed as an old man with a wise brow and pulseless heart, waging all things in the balance of reason? Is not rather the genius of history like an eternal, imploring maiden, full of fire, with a burning heart and flaming soul, humanly warm and humanly beautiful? --Zachris Topelius Training a telescope on one’s own belly button will only reveal lint. You like that? You go right on staring at it. I prefer looking at galaxies. -- Sarah Hoyt
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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.
Member 11762424 wrote:
If it's an energy-efficient bulb, this won't work.
Not necessarily true. Every bulb I have ever had has gotten hot - Incandescent, Fluorescent, and LED all produce heat. The latter two just produce less heat, so you need to run quicker.
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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
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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
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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
It's an analog solution, don't think in digital terms...unless you are well-versed in three-state logic. And yes the solution will work with CFL or LED bulbs, none of them are 100% efficient.
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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...
The "correct" answer requires knowing when a switch is "on" or "off".
Truth, James
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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 definite CORRECT solution (It's not the "official" solution) http://ericlippert.com/2011/02/14/what-would-feynman-do/[^]
Truth, James
