Three friends check into a single room in a motel and pay $10 apiece. The room
cost $25 instead of $30, so the clerk is sent to the room to give back $5. The
friends each take back $1, and the clerk is given a $2 for his trouble. Now each of
the friends paid $9, a total of $27, and the clerk received $2. What happened to
the missing dollar?''.
A classic in misdirection that never ceases to confuse, initially.
The misdirection comes from using the specific numbers resulting from the transactions in an improper way. We start with 30, followed by a 5 which is then broken up into a 2 and a 3, leading to a 27 by subtracting the 3 from the 30, plus the 2 giving us the inconceivable result. If you simply list the transactions indentifying the location of all the money, you soon see that all the money is all accounted for.
Cash in hand................Men...Hotel...Clerk
1--Men have $30............30
2--Men---$30---> Hotel.....0........30
3--Hotel---$5--->Clerk.......0........25.......5
4--Clerk---$3--->Men........3........25.......2
5--Final distribution.........3....+...25..+...2 = 30.
The misdirection comes from stating that the men paid $9 apiece for the room or $27 in all. Had the clerk given the $5 to the men and they, in turn, gave him a $2 tip for his honesty, they could have easily concluded that they paid $9.33 apiece for the room, (30 - 5 + 2)/3, making their total outlay (9.33x3) + 2 = $30.
