Sep 25, 2022
I have finally learned the answer to the riddle "there are two doors, one is safe and the other leads to death. There are two guards, one speaks the truth and the other lies. You may only ask one question"
The solution is to ask "if I were to ask the other guard, which door would they point to?"
The truthful guard will, of course, point to the dangerous door.
The lying guard will know that the truthful guard will point to the safe door, and must lie and point to the dangerous one.
Either way, whichever door they tell you will be the dangerous door and you should probably use the other door
