Suppose that Tommy Hilfiger's marginal cost of a jacket is $200 and at one of the

firm's shops, total fixed cost is $500 a day. The profit maximizing number of

jackets sold in this shop is 30 a day. Then the shops nearby from other retailers

start advertising their jackets. The Tommy Hilfiger shop decides to spend $1,000 a

day advertising its jackets, and its profit maximizing number of jackets sold jumps

to 60 a day.

What is the shop's average total cost of a jacket sold before the advertising begins?