Lights 1,2 and 3 --- Switches A, B and C - Can you solve it?

114. Lights 1,2 and 3 --- Switches A, B and C

Adjacent, plain white rooms X and Y are connected by a single door. There are no windows or additional doors in either room. There is no way to peak into one room from the other.

-In room X there are three light bulbs: 1, 2 and 3.
-In room Y there are three light switches: A, B, and C.
-Each light bulb is controlled by one and only one light switch.
-When a switch is flipped upwards, it's corresponding bulb is on.
-We do not know which light switches turn on which light bulbs.

How can you determine which light switch controls which bulb, when:
-You may choose to begin either in room X or Y.
-You may pass through the door only once.
-Once you have chosen to open the door, you must pass through, and cannot look back into the origin room after peering into the destination room.
-Any bulb/switch can be on or off at the outset.
-These are sturdy bulbs and switches: immune to short circuiting, burning out, and other mechanical failures.

???????

Submitted by GRhein · Added 5 February 2013

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Solution:

Start in room Y and turn on switch A for a few minutes, then turn it off. Next, turn on switch B and leave it on. Do not touch switch C. Now go to room X. The bulb that is on corresponds to switch B, the bulb that is off but warm corresponds to switch A, and the bulb that is off and cool corresponds to switch C.

Comments (1)

AnGuSxD 14 February 2013

I turn on Switch A and turn it of again after some minutes.
I turn on Switch B and let it be turned on.
And I don't touch Switch C.

Now I go to the next room, the Bulb that is on belongs to Switch B, the Bulb that is off but Hot belongs to Switch A and the Bulb that is off and cool belongs to Switch C.

:)

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