Find Out Which Switch Turns On Light Bulb Brain Teaser

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Discussion Overview

The discussion revolves around a brain teaser involving three switches outside a room and one light bulb inside, where participants explore methods to determine which switch controls the light bulb with only one opportunity to enter the room. The scope includes problem-solving and reasoning strategies.

Discussion Character

  • Exploratory
  • Debate/contested

Main Points Raised

  • One participant describes the scenario and asks how to identify the correct switch.
  • Another participant inquires if anyone has attempted to solve the problem.
  • A participant notes that the problem has been previously discussed and provides a link to an earlier thread.
  • One proposed method involves switching on one switch, waiting, and then checking the bulb's state (on, off, cold, or warm) to identify the correct switch.
  • Another participant reiterates the previous method but corrects the number of bulbs mentioned, indicating there is only one bulb in the original problem.
  • A different approach is suggested, where one switch is left off, one is turned on, and one is set to a middle position, with outcomes based on the bulb's state (off, on, flickering).

Areas of Agreement / Disagreement

Participants present multiple methods to solve the problem, and while some methods are reiterated, there is no consensus on a single solution. The discussion remains unresolved with competing views on the best approach.

Contextual Notes

Some methods depend on the assumption that the bulb's state can be accurately assessed through touch or observation, which may not be universally applicable. There are also discrepancies in the number of bulbs referenced in the problem.

Kevin_Axion
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This is a pretty easy problem, there is a room that is enclosed and all of the walls are opaque, there is no way to know what is going on inside from the outside (you are on the outside). There are three switches outside in which one of them has a circuit that flows to the light bulb. You can only go in one time to check which switch turns on the light bulb, how do you find out which switch is the one that turns on the light bulb?
 
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Has anyone made an attempt?
 
As far as i recall the person outside must flick a switch. Then wait a bit. Then he/she goes in. If the bulb is off and cold the switch flicked before entering is a dud. If the bulb is on, well its obvious. Something like that anyway.
 
This question is very old.
You will switch on 1 bulb and wait, then after some time switch it off and switch on another bulb and go in. There will be one bulb glowing, one hot, and one cold and not glowing
 
ashishsinghal said:
This question is very old.
You will switch on 1 bulb and wait, then after some time switch it off and switch on another bulb and go in. There will be one bulb glowing, one hot, and one cold and not glowing

There are three bulbs in your solution while there is just one in the initial problem...
 
Oh, I am sorry
 
Well, there are other methods than feeling the bulb to see if it is warm: leave one switch alone, put one switch on, and put one switch just in the middle.
If the bulb is off, then it's the first switch. If the bulb is on, then it's the second switch. If the bulb is flickering, then it's the last switch.
 

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