Three Men & A Hotel

Ok,  so yesterday a friend of mine came to me with this riddle. I am not usually someone who posts riddles, but this one really took me a while to figure out. I even looked online and couldn't find a acceptable answer. So here is how it goes;

Three men check into a hotel. The night clerk tells them it will be 30 dollars for the night. Since they are all sharing a room, they decide to split the bill, each paying 10 dollars. The men then proceed to their room. The night clerk realizes that he gave them the wrong rate. It should have been 25 dollars for the night. So the night clerk gives the bell hop five dollars and tells him to return it to the men.  On the way to the room the bell hop cannot figure out how to divide the five dollars between the three men, so he decides to give each of them one dollar and keep two dollars for himself. So each man only spent 9 dollars. So if 9 dollars X three men = 27 ( 9X3=27 ), and the boy kept two dollars for himself, then where did the other dollar go? 27+2=29