The other two switches would be for the ground floor......Put the switches on one by one.....the one which will not work for the ground floor will the one for the light bulb !!

This can be done by visiting the room once !!

if u visited the room...and switched it on any,

if the bulb lighting...that means the switch u press...is the right....if bulb is not lighten...then the other one is right..

step 1 :  switch on the 1st button for 15 min. and then turn it off.

step 2 :  switch on the 2 nd button .

step 3:   go to the room.

if the bulb is lit. the right answer is 2nd button

if the bulb is off. and it is hot.  the right answer is 1st button

if the bulb is cold . the right answer is 3rd button