riddle answer

three guys walk into a motel lobby. They need a room to shower and change, the clerk says ok 30.00$ After the guys go to the room, the clerk calls the bell boy over and tells him, I think I over charged the three guys, here is 5.00$ give it back to them. The bell boy begins going to the room and then realizes he has no change. He will give each one a dollar, and keep the other two. Each man gets a dollar back. So they only paid nine each right? Three times nine equals 27 and the bell boy kept two. Where is the last dollar?