In this paradox there is no missing dollar. The money adds up. A $25 bill, the $2 “tip” kept by the waiter, and the $3 returned the customers. 25+2+3=30.
We are influenced to think that there is a missing dollar because of the extra math that is done at the end of the example, “Three times 9 is $27. The waiter has $2 in his pocket. Two plus 27 is $29.”. This math is unneeded and only included to distract the reader.
Rowan Counterintuitive 