Puzzle Post 5

Tetsuo_Shima

Tetsuo_Shima

In Cryo Sleep
Here is a puzzle someone in the lab at work told me; hopefully it hasn't already been posted, and if it has then I apologise profusely.

There's a big, empty, square-shaped room with a lightbulb smack bang in the middle of it. The room has no windows. On one side of the room, in the middle of the wall, is a door which leads out to a corridor. A little way down the corridor is a set of three on-off switches. One of these switches controls the lightbulb in the middle of the room, and the other two do nothing! Maybe they turn on the microwave or the telly, but they don't have anything to do with the light.

The door to the room is closed, and it doesn't have any cracks underneath you can see light out of. How would you determine which one of the switches controls the lightbulb? You can fiddle around with the switches to your heart's content, but you can only open the door to check ONCE, and the door closes again after you've checked (so no leaving the door open). The switches are out of arm's reach of the door, so you can't touch them once you're holding the door open.

Please don't google it; if you get stuck I can give you some clues.

Oh, and the walls aren't made of glass or perspex or any other transparent material.
 
Ronin Storm

Ronin Storm

Administrator
Staff member
I imagine I'm not allowed to dismantle the switch box and fiddle with the wiring 'til one switch activates all three circuits?

In fact, I suspect that this isn't a puzzle to be dealt with in such a linear way...
 
Tetsuo_Shima

Tetsuo_Shima

In Cryo Sleep
Na, you don't have access to the inside of the switch box. You don't have access to the main circuit breaker, either, so even if you did have access to the switch box you'd probably get electrocuted trying to rewire it.
 
Ronin Storm

Ronin Storm

Administrator
Staff member
Okay, questions:

Does each switch work entirely independently from all the other switches? i.e. It's not a combination of switches that would lead to the light being on, just a single switch?

Does each switch just have two states, on and off?

Do we have guarantees that the lightbulb, if provided with power by switching one of the switches, will actually work?
 
Tetsuo_Shima

Tetsuo_Shima

In Cryo Sleep
The switches all act independently of each other. Just the one switch needs to be on to activate the light.

The switches are simple on-off click switches like you find in any household. No dimmer switches or anything like that.

The lightbulb is guaranteed to work when the correct switch is pressed, the filament hasn't blown or anything.
 
Wol

Wol

In Cryo Sleep
this ones ooooold.

turn one switch on, leave it 5 mins, turn it off
turn second switch on

go in room:
1) if light is off, but warm - it was the first switch
2) if light is on - its the second switch
3) if light is off, but cold - its the third switch
tada.
 
Wol

Wol

In Cryo Sleep
already have done. Was aiming for clicking "go advanced" to preview it as i couldnt remember the tag, but clicked "post"!
 
Wol

Wol

In Cryo Sleep
oooooooooooor......

RAMIREZ!

Go check the light!

:p

e2a: You may want to add in a "theres only you, and no other accomplices" clause to the original post.
 
Tetsuo_Shima

Tetsuo_Shima

In Cryo Sleep
Ramirez-Go-check-that-light.jpg
 
Ronin Storm

Ronin Storm

Administrator
Staff member
In that case, I believe the answer is:

Open the door.
Check the state of the light.
Close the door.
If light is off, flip all switches to their other setting. Light is now on.
If light is on, leave all the switches alone.

Any good?
 
thatbloke

thatbloke

Junior Administrator
Ronin Storm said:
In that case, I believe the answer is:

Open the door.
Check the state of the light.
Close the door.
If light is off, flip all switches to their other setting. Light is now on.
If light is on, leave all the switches alone.

Any good?
Click to expand...

but how do you know what single switch controls the bulb?
 
Wol

Wol

In Cryo Sleep
From that, you still wouldnt know which switch controlled the light.

If i then asked you to turn off the light, but not the kettle and microwave in the room next door...... :p
 
Ronin Storm

Ronin Storm

Administrator
Staff member
Ah, true. I misread the required end result. I can at least turn on the light for certain, though. ;)

I'll give it some more thought.
 
waterproofbob

waterproofbob

Junior Administrator
I'm not going to retype what Wol put, but what Wol wrote in his spoiler was my thought.
Not seen this one before so it may be old but I can still enjoy having solved it :D.
Although now you've said it is old I'm thinking my brain is cheating me by giving me the answer and pretending it had never heard it before.

*DAMN YOU BRAIN*
 
waterproofbob

waterproofbob

Junior Administrator
My room had a collection of scantily clad woman in it and the bulb was a bronzing light. Makes no difference to the puzzle, however it defo improves the view.
 
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