Three people walk into a motel and ask for a room. The desk clerk says a room costs 60 dollars, so each person pays 20 dollars towards the cost.
Later, the clerk realizes he made a mistake, that the room should have only been 55 dollars.
He calls the bellboy over and asks him to refund the other 5 dollars to the 3 people.
The bellboy, not wanting to make a mess dividing the 5 dollars three ways, decides to lie about the price, refunding each person 1 dollar, keeping the other 2 dollars for himself.
Ultimately each person paid 19 dollars towards the room and the bellboy got 2 dollars, for a total of 59 dollars.
But the original charge was 60 dollars. Where did the other dollar go?