Post:

You have three switches in one room and a single light bulb in another room. You are allowed to visit the room with the light bulb only once. How do you figure out which switch controls the bulb? Write your answer in the comments before looking at other answers.

Comment:

If this were an interview question, the correct response would be "Do you have any relevant questions for me? Because have a long list of things that more deserving of my precious time than to think about this!

  • NaibofTabr@infosec.pubEnglish
    2363·
    1 day ago

    This assumes several things to be true, which might not be true:

    • power is available/the upstream circuit is on (always a bad assumption to make)
    • the bulb is an incandescent type that will generate an appreciable amount of heat in a short amount of time
    • the bulb was in the off state before you changed the position of any switches, and has been off long enough to be cold
    • the bulb is connected to any of the switches
    • the bulb is connected to only one of the switches (parallel circuits are a thing, as are multi-switch lighting circuits)

    If any of the above is not true, the conclusion is invalid.

    • partial_accumen@lemmy.world
      140·
      1 day ago

      I’ll go one further:

      • Assumes the bulb is in reach. When I read the problem I assumed the bulb was in a ceiling fixture out of reach. Nowhere in the text description did it specify the physical location, except “in the other room”.
      • TeamAssimilation@infosec.pubEnglish
        42·
        1 day ago

        The biggest flaw is that it assumes you’ll add conditions you’re not explicitly told are allowed. Many, many problems in school would be trivial if changing the terms beyond what’s stated was allowed.

        • neatchee@piefed.socialEnglish
          81·
          15 hours ago

          This is often exactly what the interview question is testing. Many of these questions are not about the solution but about how the applicant approaches problems

          • TeamAssimilation@infosec.pubEnglish
            2·
            8 hours ago

            Yet they never explicitly state you’re allowed to make convenient assumptions. If the bulb was out of hand’s reach the problem would be unsolvable.

            Assuming the electrician that wired the switches is in the room would be even a more out-of-the-box solution.

    • OpenStars@piefed.socialEnglish
      9·
      18 hours ago

      Also that the labels are as shown. For all we know the internal wiring is switched, and if that were the case then some could have Up=On while others have Up=Off but not all matching.

    • SmoothLiquidation@lemmy.worldEnglish
      43·
      1 day ago

      If I asked this question during an interview and the candidate gave me this list of assumptions, I would recommend the candidate. This is exactly what I would be looking for by asking a vague question, not if they memorized the answer to a bunch of riddles, but how they thought and what their line of thought was for troubleshooting the answer.

      • NaibofTabr@infosec.pubEnglish
        18·
        1 day ago

        I tend to agree with this line of thinking. If you’re trying to hire an effective problem solver, well the first step to solving any problem is understanding the problem - the whole problem - and often more importantly the context in which the problem exists.

        And while my first reaction is to be frustrated with the person asking for a solution to such a vague problem… in the real world problems are rarely clearly stated, and frequently misstated. Investigating the apparent conditions of the problem is always necessary, and generally the fastest path to resolution.

    • taiyang@lemmy.world
      14·
      23 hours ago

      I love the idea of someone trying this stupid question irl only to realize it wasn’t even plugged in. That’s … well fuck, that’s most IT work. The convoluted approach is definitely the wrong one. Lol