Due to the resounding success of the last puzzle, here's another little brain teaser to keep you amused.
Four switches can be turned on or off. One is the lightswitch for the incandescent overhead light in the next room, which is initially off, but you don't know which. The other three switches do nothing. From the room with the switches in it, you can't see whether the light in the next room is turned on or off. You may flip the switches as often and as many times as you like, but once you enter the next room to check on the light, you must be able to say which switch controls the light without flipping the switches any further. (And you can't open the door without entering, either!) How can you determine which switch controls the light?
Comments
ok, here goes
I can't think of any more factors other than the light switch's and the light bulb so I think it has to be pretty similar to with 3 light switches only there is some extra state we can test for the light bulb, i think it takes time to heat up and cool down - they also attract dust and can be broken by dedicated turning off and on of the current if you do it for long enough - I think.
I turn the first switch on and leave it for around 30 secs and then turn it off
I turn the second switch on and leave it on for 3 minutes and then turn it off
I turn the third switch on and quickly open the door
If the light is on then it is switch 3
If the light if off but a bit warm to the touch then it is switch 1
If the ligtht is off but very warm / hot to the touch then it is switch 2
If the light is off and the bulb is cold then it was switch 4 which operates the light.
I think that might well be it...
-- Death Or Glory. Yo Ho Ho.
still puzzled
Is there a wiring diagram tacked to the wall anywhere ? Or are the walls made out of glass ?
-- Death Or Glory. Yo Ho Ho.
No on both counts
No on both counts
grr
One is the lightswitch for the incandescent overhead light
So is the correct switch the 1st switch ?
-- Death Or Glory. Yo Ho Ho.
I know the answer. Am I the w
I know the answer. Am I the winner?
arggghhh
This website freaks me out now and is ruining my life.
Are you sure there are 4 switches ?
I know the answer to this with 3 switches, and so does Chris. Paul and Phil may also remember the answer since I have puzzled them with this before. I would also like to say, smugly, that I have solved this all on my own when originally asked. It's a good one.
But if there are 4 switches then I will need to think of another answer.
In fact with 4 switches you can end up with 3 possible positive outcomes rather than the 2 you would end up with having only 3 switches. I can only think of 2 factors which would determine which of the positive outcomes is the correct one but you would need a third factor to decide in the 4 switch scenario.
-- Death Or Glory. Yo Ho Ho.
it is possible with 4 switche
it is possible with 4 switches
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