Richard Cromwell/Home

Suppose there are three sailors on weekend leave. They take it upon themselves to rent a motel room for drinking, fun, and discussions of both irradiated beef and inert shielding gas.

Upon arrival, the desk clerk tells them that it will cost thirty dollars for the three of them. Each sailor pulls a ten-dollar bill from his wallet, giving it to the desk clerk. The sailors retire to their retreat, already discussing their latest applications of Argon.

A little while later, the desk clerk realizes he has made an error. The motel policy gives service members a five-dollar room rate discount, yet he forgot to apply the discount for the room that they have reserved. The clerk calls the busboy over, handing him five dollars and directing him to take the refund back to the sailors.

The busboy, with a healthy respect for opportunism, has no idea how to split up five dollars evenly amongst the three seamen. He does, however, devise a solution of giving each man a one dollar refund. This allows the busboy to pay the sailors for their discounted room and pocket the other two dollars for himself.

He knocks on the door, returns a single dollar to each man, then goes about his business.

Each sailor paid nine dollars = $27 total

The busboy kept two dollars = $2 total

Where's the extra dollar?