Yeah, originally its 3 guys at a hotel, charged $30, manager catches that they should have only been charged 25. They give back $1 to each guy and keep 2. Each guy paid $9 (for $27) plus the $2 that was kept looks like $1 missing.

Nothing is missing because the $25 for the room + $3 that was given back + $2 that was kept = $30.