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3 light bulbs and 3 switches

   here's another one guys..(probably an ea 10-Nov-01 me
      Suppose 3 switches A, B, C correspond to 10-Nov-01 gokul

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me Posted on 10-Nov-01 02:56 AM

here's another one guys..(probably an easy one..)
there are 3 light bulbs in the second floor of a house. The three individual switches for these light bulbs are located on the first floor of the building.( you can't see the bulbs from the first floor). Going from first to second floor only once, how can a person figure out which switch lit which bulb?
hope i made the question clear enough..
gokul Posted on 10-Nov-01 10:45 AM

Suppose 3 switches A, B, C correspond to three bulbs AB, BB, CB respectively.

Then press A so that AB turns on.
After a while, press A down.

Then press B and go to the second floor. The one that is on BB.
Touch the other two bulbs with hand. The one that is warm is AB. The cold one CB.
In case, you can not touch them with hand, then you have to look for other alternatives such as gathering of moths or other insects.