Three women check into a motel room that advertises a rate of 27 per night. They each give 10 to the porter, and ask her to bring back three dollar bills. The porter returns to the desk, where she learns that the room is actually only 25 per night. She gives 25 to the motel desk clerk, returns to the room, and gives the guests back each one dollar, deciding not to tell them about the actual rate. Thus the porter has pocketed 2, while each guest has spent 10 - 1 =9, a total of 2+3 x 9=29. What happened to the other dollar?