Case 002
The Swapped Envelope
A sealed envelope was replaced with an empty one.
Rule: exactly one suspect is guilty. The guilty suspect lies. Every innocent suspect tells the truth.
Peyton
“Either Hayden or Kai is guilty.”
Hayden
“Rowan is guilty.”
Taylor
“Rowan is innocent.”
Kai
“Either Peyton or Hayden is guilty.”
Rowan
“Hayden is guilty.”
Who is guilty?
Solution: Hayden
If Hayden is guilty, Hayden's statement is false and every other statement is true. Testing the other suspects creates at least one contradiction.