Sometimes, the good old riddles are amazing tests of logic.
A girl is stuck in a labyrinth, and after many hours of wandering through it, comes upon two majestic doors, with large, round iron door-knockers with ancient symbols on them. A wooden sign placed in the middle of both of them, states thus:
Behold!
Two doors stand before you,
One door must speak the truth,
One door only utters lies.
One of them leads to certain death,
The other, to sanctuary and beyond.
Knock on each door, and you may ask it a single question.
Listen well, lest it’s answer be your last.
Choose wisely.
How does the girl get out of the labyrinth?
FULL marks, Zeeshan!
Perfect logic as well as detailing of explanation.
To start with We will make an assumption,
The doors are called A and B, and A is the correct one.
The liar Door is called Mr.L and the truthful Door is called Mr.T
She should ask Mr.L: “What would Mr.T say if I asked him which is the correct door?”
L replies, “Door B.” He knows T will say the right door (that is Door A) and He has to lie, so He goes for B.
The she should ask Mr.T: “What would Mr.L say if I asked him which is the correct door?”
Mr.T replies, “Door B.” Mr.T knows that A is the right door and that Mr.L is a liar. Mr.T is honest, so he will tell her Mr.L will give you a dishonest answer ie.Door B.
Now, assuming she didn’t know which was Mr.T and which was Mr.L, she could ask either of them and still get “Door B” as her answer. So she should choose door A and fly to freedom.