hi friends,

This is Madhu, I got a riddle for you all guys...

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?

All the best buddies!

luv
Madhu