The manager of a home store is buying lawn chairs to sell at his store. Each pack of chairs contains 10 chairs. The manager will sell each chair at a markup of 20% of the wholesale cost, plus a $2.50 stocking fee.

a. Write an equation that represents the retail price of a chair, r, in terms of the wholesale price, w.

b. Use your equation to calculate the retail price of the chair if the wholesale price is $8.40.

c. Use your equation to calculate the wholesale price if the retail price is $13.30.