Three men needed a two-seat flying machine. Nobody broke the rules
A pilot's flying machine only seats two. One day he takes a passenger up, climbs to a thousand feet, and is then told by a second passenger, already aboard, that the engine sounds wrong. Somehow three men made the flight in a two-seat machine, and none is related to the pilot. Mr. Wilson, telling the story, says it's simple: his own uncle and his own nephew were both on that flight. How can one man be both someone's uncle and nephew at once, without any marriage breaking the usual rules?
Reveal the answer
Two men each married the other's mother, and each had a son by that marriage. Those two sons are then simultaneously each other's uncle and nephew, with no prohibited relationship involved, so Wilson's uncle and his nephew were one and the same man all along. Dudeney published this as 'Wilson's Poser' in Amusements in Mathematics (1917).
— Henry Ernest Dudeney, Amusements in Mathematics — Thomas Nelson & Sons, 1917
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