Alice wins $50 from a scratch-off.
Bob says, “Hey, you owe me $100.”
She says, “Here’s $50, and I’ll owe you $50.” She hands Bob $50.
Charlie jumps in: “Bob, you owe me $100.”
Bob: “Here’s $50; I still owe you $50.” He hands Charlie $50.
Alice: “Charlie, you owe me $100.”
Charlie: “Here’s $50; I owe you $50.” He hands Alice the $50.
Bob: “You still owe me $50, Alice.”
Alice hands over $50.
Charlie: “Bob, you still owe me $50.”
Bob hands over $50.
Alice: “Charlie, you still owe me $50.”
Charlie hands $50 to Alice. Alice keeps the $50 in her pocket. Was anyone cheated?
The Palindromic Prisoners
There are many different solutions to this puzzle, but the simplest thing is for the prisoners to all agree to say the same digit.
Solutions were submitted by Bob Conger, Stephen DiCillo, Moshe Gelbwachs, Akshar Gohil, Christina Marinello Swan, Jerry Miccolis, Jacob Ogle, Roger Sarvate, Rick Sutherland, Victor You, and Jeffrey Zheng.
