<P> The missing dollar riddle is a famous riddle that involves an informal fallacy . It dates back to at least the 1930's, although similar puzzles are much older . </P> <P> Although the wording and specifics can alter, the puzzle runs along these lines: </P> <P> Three people check into a hotel room . The clerk says the bill is $30, so each guest pays $10 . Later the clerk realizes the bill should only be $25 . To rectify this, he gives the bellhop $5 to return to the guests . On the way to the room, the bellhop realizes that he cannot divide the money equally . As the guests didn't know the total of the revised bill, the bellhop decides to just give each guest $1 and keep $2 as a tip for himself . Each guest got $1 back, so now each guest only paid $9, bringing the total paid to $27 . The bellhop has $2 . And $27 + $2 = $29 so, if the guests originally handed over $30, what happened to the remaining $1? </P>

Three guys share a room that costs $30