1. SubscriberPureRWandB
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    11 Aug '12 20:57
    Three switches outside a windowless room are connected to three light bulbs inside the room. How can you determine which switch is connected to which bulb if you are only allowed to enter the room once?
  2. Standard memberforkedknight
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    12 Aug '12 15:33
    Originally posted by PureRWandB
    Three switches outside a windowless room are connected to three light bulbs inside the room. How can you determine which switch is connected to which bulb if you are only allowed to enter the room once?
    Are they LED's?

    This puzzle isn't going to make sense in 20 years 🙂
  3. SubscriberAThousandYoung
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    12 Aug '12 18:46
    Originally posted by forkedknight
    Are they LED's?

    This puzzle isn't going to make sense in 20 years 🙂
    nope, incandescent bulbs
  4. Standard memberSwissGambit
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    13 Aug '12 04:24
    Originally posted by PureRWandB
    Three switches outside a windowless room are connected to three light bulbs inside the room. How can you determine which switch is connected to which bulb if you are only allowed to enter the room once?
    Reveal Hidden Content
    Leave the left switch on for an hour. Turn it off and turn the middle one on. Enter the room. The hot bulb is connected to the left switch, the lit bulb is connected to the middle switch, etc.
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    13 Aug '12 04:35
    I guess it would be possible to trace each wire with your hands by walking through the window with a hand tracing two of the wires and using the rules of elimination to figure out the other light bulb and switch.
  6. Standard memberSwissGambit
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    14 Aug '12 01:22
    Originally posted by Jono3000
    I guess it would be possible to trace each wire with your hands by walking through the window with a hand tracing two of the wires and using the rules of elimination to figure out the other light bulb and switch.
    There is no window.
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    15 Aug '12 02:09
    Turn one switch on After a half hour turn it off and turn another on. Then go in the room. One bulb will be on, corresponding to the switch you just turned on. There will be two bulbs turned off; but one of them will be warm, corresponding to the switch you turned on for a half hour. The cold one will correspond to the switch that was never turned on.
  8. Standard memberforkedknight
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    15 Aug '12 19:41
    Originally posted by AThousandYoung
    nope, incandescent bulbs
    Now solve for LED's
  9. Standard memberSwissGambit
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    16 Aug '12 05:08
    Originally posted by forkedknight
    Now solve for LED's
    Take a sledge hammer to the sheetrock. Trace wiring. This solves without even entering the room. 😏
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    23 Sep '12 04:40
    Originally posted by forkedknight
    Now solve for LED's
    Same as Jayteedee's except you turn one on and wait till it burns out? then before going in turn one of the other two on. Can you tell if an LED bulb is burned out? I mean besides it doesn't give any light. If not I guess you could take some kind of meter in there or something
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    26 Sep '12 00:48
    LED

    Turn the left switch on and leave it for a few days.

    When you come back turn the middle switch on

    Enter room

    Dim light belongs to the left switch

    Bright one to the middle etc
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    26 Sep '12 15:231 edit
    Enter the room, replace the leds with bulbs of 3 known different resistances, noting the positions

    Exit the room and take apart the switches, then use a multimeter to determine which switch is connected to which bulb.
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    28 Sep '12 13:30
    Originally posted by iamatiger
    Enter the room, replace the leds with bulbs of 3 known different resistances, noting the positions

    Exit the room and take apart the switches, then use a multimeter to determine which switch is connected to which bulb.
    A proper geek's solution. I salute you, sir.

    Richard
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    29 Sep '12 13:18
    Find someone else to stand outside the room and turn each switch on and off in an agreed order while you watch the bulbs from inside the room.
  15. Standard memberThequ1ck
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    09 Oct '12 08:58
    Put one switch on. Wait 5 minutes and put another switch on.

    The bulb that is out will be the switch that is off, the bulb that is hot will
    be the first switch you put on and the bulb that is cooler will be the last
    switch put on.
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