Holmes wrote:" The problem of the Three electrical switchs "
In all the problems that require lateral thinking, this is the one I like most.
First of all I want to say that there arenÂ´t any types of "tricks". It is a problem that, with the pieces of information given, it can be resolved. Here it goes:
You have deserted room with only one lightbulb one the roof. The electrical switch that activates the light is outside the room. However, there isnÂ´t only one electrical switch, there are three. Only one switch activates the light (The light works, obviously). The problem consists on the following: the door of the room is closed. You have all the time you want to "play" with the switchs. You can use any combination you want with them, but you can only go in the room once. At the moment you go out the room, you must be capable to say: "This is the switch that activates the light."The three switchs are in the same position: Off.
LetÂ´s get it clearer: while the door is closed and you are outside, you can entertain yourself with the switchs as you wish. But, there will be a moment where youÂ´ll have to decide to go in the room. There are no problems. You do it. But when you come out, youÂ´ll have to be able to answer the question orf which of the three switchs is the one that activates the light?
One more time: the problem hasnÂ´t got any type of tricks. It isnÂ´t that you can see under the door or that there is a window on the door. It is a problem that can be resolved.
LetÂ´s see how you reason, shall we?
Sayumi wrote: Pretty sure I know this one ;D
1.Turn on two of the switches
2.Wait for about 30min
3. Turn off one of the switches
4. Go into the other room
The 3 possibilities are:
-the light is on -> it is the switch which is still on
-the light is not but the lightbulb is warm when you touch it -> it is the switch you just turned off
-the lightbulb is not on and cold-> it is the third switch you never turned
5.Go out of the room and confidently answer the question
Exploit the fact that a light bulb emits two types of 'information'. Light and heat. Switch on two of the three switches, say a and b, leave c off. Wait a while, then switch off b. Go into the room. If the light is on and bulb is warm then a is the correct switch. If light is off and bulb is warm the b is the correct switch. Finally, if light is off and bulb is cold then c is the correct switch.
Then proceed to Sayumi's step 5.
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