257 replies to this topic

[arwritergal]

Maybe I'm just being simple-minded, but why don't you just go into the room with the lamps, pick them all up and go back into the room with the swtiches? Plug the lamps in, and flip switches to your heart's content while seeing which switch does what. It's just a thought.

[Kalinighta]

This is a very simple riddle, all that it requires is logice, all that you need to do is turn on 1 switch and kepp it on, then turn on another for 3 minutes, turn it off, and walk into the room, the one that is warm is the switch that you turned on for 3 minutes, the one that is one is the sitch that your turned on and kept on.

[CygnusX1]

Bulbs - Back to the Logic Puzzles
This is one of my favorite logic puzzles (Edit: it is more a practical than a logic puzzle).
Imagine you are in a room with 3 switches. In an adjacent room there are 3 bulbs (Edit: let's say in lamps which are on a regular table) - all are off at the moment, each switch belongs to one bulb. It is impossible to see from one room to another. How can you find out which switch belongs to which bulb, if you may enter the room with the bulbs only once?

Edit: No help from anybody else is allowed.
Edit: Find out which switch belongs to which bulb - identify all 3 switches (so find out what bulbs are switches 1, 2 and 3 connected to)

Spoiler for Solution

Bulbs - solution
Keep the first bulb switched on for a few minutes. It gets warm, right? So all you have to do then is ... switch it off, switch another one on, walk into the room with bulbs, touch them and tell which one was switched on as the first one (the warm one) and the others can be easily identified ...

O.K. Either there is something missing to this puzzle or that has got to be the dumbest thing I have ever heard. You have turned on one bulb and left it on for a few moments so it can get warm, then you shut it off and turned on another one to get it just a little warm. At this point there is no reason to enter the room since simple process of elimination allows you to designate the third switch to the only bulb not turned on.

[HAMST3RMAN]

Keep one on 4 a long time, and turn it off. Turn on the next switch and go in 1st switch's would be hot, 2nd would be on.

[tink]

turn one on for a little while turn it off then turn on a differant one walkin the room the cool bulb is the one you didnt turn on and the one on is the one you just turned on the hot one was the first you turned on

[dogliver]

Turn on all 3 switches.
Wait 5 minutes
Turn off switch # 1
Wait 5 minutes
Turn off switch #2 and go into the room.
Burning bulb is switch #3
Very warm unlit bulb is #2
Cooler unlit bulb is #1

[thinkaboutit]

well if you could go into the room with the lights you could unscrew one and go into the room with the switches and click one on and go into the room and guess it out

[Bije]

I will swich the first swich on and let the bulb from that swich for a few mins or hours on so it can become hot and then swich the second one, go to the room, se which one is hot, that is the first swich and the second swich is the other that is not hot but on, and the third swich is the bulb that is off

[Catlo]

Possibility 1:
Step 1) enter room
Step 2) set up mirrors
Step 3) use mirrors to determine
<_<
Possibility 2:
1) enter room
2) set cameras.
3)watch and learn

[scuttill]

The safe way to successfully do this puzzle ...

Spoiler for Don't burn yourself

Turn on one switch and leave on for a long time (e.g. an hour) - pray the bulb doesn't burn out in this amount of time. Then, turn off that switch (#1), and turn on switch (#2). Now immediately go in the room.

You can quickly see which one switch #2 controls (it's the only light on). Now, for the love of your skin, do NOT touch the other two bulbs. In case you missed this lesson in fire-safety, you never grab a doorknob to see if it is hot in a fire, you always approach with the backside of your hand - it is the most sensitive. You can feel the heat before you make actual contact. Do the same here! Approach the other two bulbs with the back of your hand to see which is hot. The hot one is to switch #1; the cold one is to switch #3 (having never been turned on).

That said, I'm not sure what to do if you are in an environmentally-friendly puzzle that uses compact flourescents instead of traditional, wasteful incandescent bulbs. The CF bulbs may not be as reliable in this solution. The don't burn as hot, don't waste as much energy, and don't really respond well to suggestions of leaving a switch in the "halfway" position. I wonder if there is such a solution to a cool, energy-efficient bulb puzzle.