Puzzles
Three guests pay $30 for a room, get $5 back, and $1 seems to vanish. Where did it go?
Three guests split a $30 hotel bill, $10 each. The manager realizes it should have been $25 and sends the bellhop back with $5. The bellhop pockets $2 and gives each guest $1 back. Each guest paid $9, for $27 total; add the bellhop's $2, and you get $29. Where did the missing dollar go?
Reveal the answer
Nowhere: the arithmetic is a trick. The guests paid $27 total: $25 went to the hotel and $2 to the dishonest bellhop, which already accounts for the full $27. Adding the bellhop's $2 back on top of the $27 is the error, since those two figures were never meant to be summed. First published by R. M. Abraham in 1933, it's been popularized for decades since as a classic lesson in how a plausible-sounding sum can mislead.