So last week, I posed this riddle:

“You’re standing in a room with two doors. One opens to instant death, and the other leads to life. Standing in front of each door is a robot guard. With no other way out of the room, you must choose a door to enter. You may ask one question, which each robot will answer. One robot is programed to always lie. The other robot is programed to always tell the truth. What question could you ask that will help you identify the door to life?”

As promised, here is the answer:

“If I asked which door opened to Life, which door would the other robot point to?”

The robot programmed to always lie would say the other robot is going to pick the door that opens to death, and would point to that one. The robot programmed to always be truthful would say the second robot is going to pick the door that opens to death (because the other robot is programmed to lie). With both robots pointing to the same door, that means that the opposite door leads to life.

Can you come up with a different answer?