Here's an interesting puzzle form today's Guardian. See if you can figure it out (don't give it away if you already know the answer).
There are three switches in the basement. One of them controls a single lightbulb in the attic. You are tasked with taking one trip to the basement, where you can flip the switches on and off as much as you like, and then taking one trip to the attic. After this one and only trip the attic, you have to figure out which switch controls the lightbulb. How do you do it?
To clarify, you cannot see the lightbulb from the basement.
There are three switches in the basement. One of them controls a single lightbulb in the attic. You are tasked with taking one trip to the basement, where you can flip the switches on and off as much as you like, and then taking one trip to the attic. After this one and only trip the attic, you have to figure out which switch controls the lightbulb. How do you do it?
To clarify, you cannot see the lightbulb from the basement.