Karen, Lean, and Nico went to Yellow Cab to eat. After they ate, the cashier said that the pizza cost $30. Lean, Karen and Nico split the payment with $10 each. Later the cashier realizes the bill should only be $25. To rectify he gives Alvin the delivery boy five dollars in singles to return to the customers. On the way to the door Alvin realizes that he cannot divide the money evenly. As they didn’t know the total of the revised bill, he decides to give each customer a dollar and keep two for himself. Lean, Karen and Nico were glad to be have been notified and went home.

Now that the customer have been given a dollar back, each has paid $9. Three times nine is 27 and Alvin has $2. Two plus 27 is 29. If the customers originally handed over $30, what happened to the remaining dollar?