A used car salesman sold two cars and received for each car. One of these transactions yielded a percent profit for the dealer (compared to his purchase price), whereas the other amounted to a percent loss. What is the dealer’s net profit (or loss) on the two transactions?
Source: NCTM Mathematics Teacher 2006
Let represent the purchase prices of the cars. Suppose the dealer makes a profit on the first car and sustains a loss on the second car.