A perfectly competitive industry consists of many identical firms, each with a long-run average total cost of LATC = 800 - 10Q + 0.1Q² and long-run marginal cost of LMC = 800 - 20Q + 0.3Q². The industry's demand curve is Q^D = 40,000 - 70P. In long-run equilibrium, the total quantity purchase by consumers is ____.

Question

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In long-run equilibrium, price equals the minimum of LATC. Setting the derivative of LATC with respect to Q to zero, we find Q = 50. Substituting Q = 50 into LATC gives the minimum LATC = 550. Setting P = 550 in the demand curve Q^D = 40,000 - 70P, we find Q^D = 1,500.

A Perfectly Competitive Industry Consists of Many Identical Firms, Each