Problem Solver

Three men are travelling in a car.The car breaks down and they look for a mechanic to repair the car. They are charged 30 dollars and each pay 10 dollars to make up the charge. So after the car is repaired they are set to go. The mechanic realizes that he had over charged them by 5 dollars and he gives his son to take back the change to the three guys. The son thinks to himself " How can 3 people share 5 dollars?" and so he takes 2 dollars for himself and gives back each of the three 1 dollar.

Effectively this means that each of the three guys paid 9 dollars because they have 1 dollar change from the 10 dollars they each paid. 9 dollars times three guys equals 27 dollars plus the 2 dollars the boy took comes to 29 dollars. What happened to the 1 dollar???