There are two doors. Behind one is safety; behind the other is certain death. There are two guardians of the doors; one is known to always tell the truth. Other always lies. You have only one question to ask to find out which door is safe to go through.

What question do you ask?






Answer:

Would the other guard say that this is the safe way to go?

(answer will be same for both the guardians. If the answer is "yes" go the other way; if the answer is "no" go the same way.)