Supply in a Competitive Market - End of Chapter Problem Martha is one producer in the perfectly competitive jelly industry. Last year, Martha and all of her competitors found themselves earning economic profits. a. If entry and exit from the jelly industry are free, in the b. Given the entry or exit identified in part a, the industry long run, the number of suppliers in the industry will supply of jelly will c. As a result of the supply change identified in part b, d. As a result of the price change identified in part c, in the price of jelly will the long run, Martha will her output and will earn economic profit