Brainteaser: You see a house with two doors. One door leads to certain death, and the other door leads to freedom. There are two guards, one in front of each door. One guard always tells the truth, and the other guard always lies. You don’t know which guard is which or which door leads to freedom. You can ask one guard one question. What question should you ask to find the door to freedom?
Answer: Ask one guard, “If I were to ask the other guard which door leads to freedom, what would he say?” Then choose the opposite door of what the guard tells you.
