Three brothers stopped at a motel and got a room. The clerk said it was $30 for the night. They each reached into their pockets and gave the man a ten dollar bill. Later the manager stopped in and upon learning that the room was rented, told the staffer that the room only cost $25 this week, not the $30 that he had collected. So he handed him 5 one dollar bills and told him to give the men their money back. Well along the way he got to figuring, five one dollar bills and only three of them, so he put two of the bills in his own pocket and gave the brothers back each a dollar.

So the room originally cost $30, and each had paid $10, and gotten back one dollar. So each actually had paid only $9. There were three of them, so that is $27, plus the two dollars the clerk has in his pocket makes $29. What happened to the other dollar ?