Question: Sara is a dot.com entrepreneur who has established a Web site at which people can design and buy sweatshirts. Sara pays $1,000 a week for her Web server and Internet connection. The sweatshirts that her customers design are made to order by another firm, and Sara pays this firm $20 a sweatshirt. Sara has no other costs. The table sets out the demand schedule for Sara's sweatshirts.

           Price                               Quantity demanded
(dollars per sweatshirt)                (sweatshirt per week)

               0                                          100

              20                                           80

              40                                           60

              60                                           40

              80                                           20

             100                                            0

Calculate Sara's profit-maximizing output, price, and economic profit.