The Cookie Problem

This semester we used a simple modeling problem as one of the questions on our Precalculus final exam:

"The Fresh Bakery currently sells 1000 large chocolate-chip cookies each week for $0.50 a piece. The bakery would like to increase its revenue from cookie sales by increasing this price. A survey convinced the manager that for every $0.10 increase, the bakery would sell 70 fewer cookies each week. At what price should the cookies be sold to maximize the revenue to the bakery?"