Complete solutions are required. Unless stated otherwise, calculators are not permitted and you may leave your answer in a calculator ready format. 1. 5 marks Companies are often interested in minimizing their average cost function. Eco- nomic theory dictates that this should happen precisely when the average total cost is equal to the marginal cost. (a) Give a (brief) explanation of why this is actually true. (6) Consider a company whose cost function is given by C(r) = x3 - 200x + 15000.c. Determine the number of units the company should produce in order to minimize the average cost of producing each unit. () What is the lowest average cost per unit this company can achieve