Logic Locks
You stand before two doors, one leads to safety, one to death. Each door has a guard: one always lies, one always tells the truth. You can ask one question to one guard. What do you ask?
“If I asked the other guard which door leads to safety, what would they say?” Then pick the opposite.
You’re imagining you are trapped in a room with no doors or windows. How do you get out?
Stop imagining the room.
At 3:15, what is the angle between the hour and minute hand?
7.5 degrees.
In a town where shaking hands is forbidden with those who’ve shaken before, how do people know who to greet?
They track interactions mathematically.
A clock stops for five minutes at 3 PM. What time is it when it restarts?
Still 3:05 — nothing special.
A man is found hanging from the ceiling in a locked room. Below him is a puddle of water. What happened?
He stood on a block of ice that melted.
A man is buried up to his neck in the rain but never gets wet. Why?
He’s already dead.
In an infinite hotel, all rooms are full. A new guest arrives. How can he still get a room?
The hotel is infinite.
A man can’t move or speak but somehow leaves a room. How?
He imagines leaving.
A man drowns in a river that doesn’t exist. How?
It’s a dream.
A town has only liars and truth-tellers. Three people give you three different answers to the same yes/no question. What’s going on?
At least one person is random — not bound to truth or lies.
Two deadly buttons: one says “Pressing me kills you instantly,” the other “Pressing me saves you.” What do you do?
Press neither — survival through inaction.
A man throws a rock straight up, but it never comes down. Why?
Zero gravity.
A guard alternates truth and lies every time he speaks. How do you find the right path?
Ask the same question twice or wait for the pattern.
A line of people each wears a hat. They can see others’ hats but not their own. How can they guess correctly?
They use a pre-decided parity or pattern system.
All the windows of a house face south. A bear walks by. What color is the bear?
White (it’s at the North Pole — polar bear).
A man looks at a picture and says, “That man’s father is my father’s son.” Who is in the picture?
His son.
A man lies in the desert, dead, but has no thirst. Why?
He was already dead before he could be thirsty.
A room has no door, ceiling, or floor, yet a man breathes fine. How?
It’s not a physical room — it’s conceptual.
A door opens when you speak truth and locks on lies. What do you say to escape?
“This door will open if I speak the truth.”
100 prisoners each wear a red or blue hat and can see everyone else’s hat but not their own. They must all guess simultaneously. How do they survive?
They pre-agree on parity (odd/even) of visible hats to deduce their own.
A man pushes his car to a hotel and goes bankrupt. What happened?
He’s playing Monopoly.
You’re trapped in a room with a mirror and a table. How do you escape?
Look in the mirror, “see” what you saw, “take” the saw, cut the table in half—two halves make a whole (hole)—climb out.
A labyrinth has two exits, one fatal, one safe, with no markings. How do you survive?
Use trial, error, or markers; logical deduction.
A button kills instantly but must be pressed. What’s the solution?
Realize “must” is false — you don’t have to press it.