Question: A man challenges the greatest chess player in the world to two games of chess. He guarantees that he will win or tie at least one of the games for sure. To be even more cocky, the man says he will play both games at the same time.
How does he guarantee he wins or ties at least one game?
Answer: He just copies the great chess player's moves exactly on both boards, going first on one and second on the other. He waits for the great player to make his first move on the first board and copies this on the board he goes first on. He then waits for the chess player to make his move on that board and copies it on the other board. He alternates moves on the two boards like this until the game is over and he ties on both or wins one and loses one.