I dont know how well this riddle will work in written form, this reminds me so much of the round and round reasoning JW (my mom) uses daily.
Three men go skiing, and forgot to book their hotel rooms. They find a hotel with only one room left, and the three agree to take it and share. The Price is 30 dollars, each man pays 10 dollars, and they go to their room. When they arrive they discover the room is very dirty, and they call down to the front desk and complain. The hotel manager feels bad and tells the bell hop to return 5 dollars to the men for their troubles. The bell hop finds himself outside the room, and can not figure out how to return 5 dollars to 3 men. So instead he gives them each 1 dollar back and keeps 2 for himself.
So the men each paid 9 dollars for their room
9 x 3 = 27 dollars
the bell hop kept 2 dollars
27 + 2 = 29 dollars
Where did the missing dollar go?