Most of you already know the aswer

3 men had been camping and got stranded. After a long days walk they come to a small motel. When they enter they ask the receptionist how much a room is, she quickly responds only $30 and the rooms are large enough to share. Relieved the 3 men each hand her a $10 bill and leave their bags for the bell boy. As the bell boy is getting their things together the receptionist remembers that the motel was giving a small discount and gives $5 to the bell boy to give back. Walking to the room with the bags the bell boy pockets $2 because he knew they didn't know they were getting anything back. He hands each of the men $1. Now each man has paid $9 3x9 is 27 plus the 2 the bell boy pocketed makes 29 where did the other dollar go?