14.

a. Supply curves are steeper over long periods of time than over short periods of time. b. Buyers of goods tend to be more responsive to price changes over long periods of time than over short periods of time. C. The number of firms in a market tends to be more variable over long periods of A time than over short periods of time. d. Firms prefer to change their prices in the short run rather than in the long run. 14 . According to the theory of contestable market, J a. the mere threat of potential entry encourages oligopolists to hold profits near the competitive level. b. firms must actually enter an industry if prices and outputs are to be held near the competitive level. c. many firms in an industry market make it contestable. d. high costs of entry make market markets more contestable. 15. Hilda's Hair Hysteria earned $3,750 in total revenue last month when it sold 125 ha month it earned $3,600 in total revenue when it sold 90 haircuts. The price elasticity 0103 for Hilda's Hair Hysteria is D 20