Im fucking higher than a kite right now and knew the answers to those before I was even finished reading them. Lets start with some actual challenging ones, here's a good one.
You are in a 4 story building. No windows, no mirrors, nothing. there is a staircase that runs from the bottom to the top floor. In the bottom room, there is a single light bulb. Unfortunately the light switch for it is in the top floor. Here's where it gets tricky,, There are 3 switches, one of the switches work, the other 2 don't. Currently you are in the top room, and are only allow to go check the light bulb once. You CAN'T go back upstairs AND you have to be a 100% certain which switch it is that turned the bulb on. HOW???
