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!
- Use the heat of the bulb to determine if it was on. (Shows you can memorize stupid interview questions)
- Ask a team member to coordinate with you in the other room. (You’re a team player)
- Use a cable locator (Proper tool for the trade)
- Put your phone in the other room, stream camera feed to your work laptop (The tech approach)
- Unscrew the bulb. Now you know that no switch controls the bulb (Exposing the flaw in the task’s phrasing)
- Open switch panel and disconnect one switch. Wait a day. If no one complains, disconnect the second. Wait a day. If no one complains, it’s probably the third. For good measure, disconnect the third switch. If still no one complains, remove all switches and the lightbulb, since they’re not needed anymore. (The Sysadmin approach)
I am the sysadmin and I approve this message.
Open switch panel and disconnect one switch. Wait a day. If no one complains, disconnect the second. Wait a day. If no one complains, it’s probably the third. For good measure, disconnect the third switch. If still no one complains, remove all switches and the lightbulb, since they’re not needed anymore. (The Sysadmin approach)
I used this method a few months ago in my breaker box. I needed to make room in it for an EV charger.
So, how’s the freezer doing by now?
It’s funny to read the reactions and the people not understanding that programming questions are not enough to judge you. We need people with functioning brains and that usually means problem solving skills. And sometimes the problems are fucking idiotic! Nobody cares about the light switches. We want to see how you think. We want people who don’t give up if they can’t look it up.
You think you’re hot shit because you learnt the latest trendy language? I’ve wasted entire days with people like that because they couldn’t be fucking arsed reading error messages and figuring things out by themselves.
Stupid interview questions show you nothing about how people think. Might as well ask them their astrological animal and blood type
On the contrary, someone can learn a lot from a question like this. If they immediately spit out the answer, then I know that they studied and came prepared to answer common questions like that. If they give a response like the OP, then I know they are an asshole to work with. If they don’t know, do they ask follow up questions or ask for a moment to think can tell me how well they like to work in a group. If they talk about asking a coworker vs researching a solution independently first can tell me how they may react to a brick wall of a problem. Last thing that comes to my mind, is how long they try before giving up. That can be a good indicator for how they treat work meetings - do they push through the task one at a time and in exact order, or do they have the social skills to know when it is time to shut up and move on to the next thing.
Replace the Lightbulb with a paperclip then flip the switches until you hear the circuitbreaker trip
All three switches are on the same circuit.
The answer is to turn on the first one and wait ten minutes. Then turn it off and flick on the second switch and go and look at the light. If the light is off and the bulb is hot it is the first switch if its off and cold its the third switch and if its on its the second switch.
Hope this helps.
that assumes one of the three switches is able to turn the light on, which is not stated in the question
“Do you have any questions for us?”
“You have three engineers in one room. The order comes to let one go. Who do you let go and why?”
“Wut?”
how was I holding on to three engineers in the first place? I only have two hands
If you get that as an answer you know enough.
Dead serious question: I have only ever worked in the public sector (state level and local municipality) but often see or hear about these seemingly idiotic “interview questions” on television (and obviously memes).
Is this:
- just a meme
- just a joke
- an actual phenomenon in the private sector
If 3, what on earth is its purpose and what could the interviewer possibly find out about the applicant by asking this?
I’m calm.
In the private sector, I once was asked to come up with 12 uses for a kettle. I said make 12 cups of coffee. I didn’t get the job.
In the end it all boils down to heating water
That’s why you don’t make a 10 figure salary. It can also be used to boil oil to throw on invaders when the office is under siege
I think I was asked this very question in an interview once. I think I answered something along the lines of ‘If you have a light switch like that here in the office, the first thing I would recommend is calling in an electrician to change and move the switch to the correct room. Why would you have a light switch that controls a light in a different room and apparently two switches that do nothing??’
Got the job.
The bathroom where the switch is prone to get splashed?
Sure, but I would still argue the bathroom light switch should be located, I don’t know, next to the bathroom door? And most definitely there shouldn’t be two totally useless switches there.
I don’t think I would like to work for a company that struggles this much with light switches…
maybe dont care. hit all 3 of em. answer is: i have figured out that one of the 3 switches controls the bulb (or not)
You have to report back which individual switch it is such that another person is able to control the light bulb reliably because they know which switch
But they are able to control the lightbulb by flipping all three switches.
