The Honest and Dishonest Guards

You’re in a room with two doors. There’s a guard at each door. One door is the exit, but behind the other door is something that will kill you. You’re told that one guard always tells the truth and the other guard always lies. You don’t know which guard is which. You are allowed to ask one question to either of the guards to determine which door is the exit. 

What question should you ask?

Exit door

Here is that question! 

Source 

Question to Find The Exit Door

What was the situation? 

What if I tell you that you have to ask only one question to anyone & choose the opposite door? Yes, be patient & read further.

Ask anybody this question.

"What would other guard answer if I ask him which one is exit door?"

Now there are two possibilities.

1. If the guard is truth telling then he knows other guard would lie & point the door leading towards the death. So he will point that door.

2. If the guard is lying then he knows other truth telling guard would have pointed right door.But in order to lie, he would point to opposite door!