There are three switches downstairs. Each corresponds to one of the
three light bulbs in the attic. You can turn the switches on and off and
leave them in any position.
How would you identify which switch corresponds to which light bulb, if you are only allowed one trip upstairs?
Post the answer if you know it.
In the meanwhile, here is the solution to yesterday's puzzle.
Answer: Change one of the + into a 4: 5 + 545 = 550.
