Question 4 (45 marks) (a) 25 marks The following table relates to a perfectly competitive firm, which sells its product for E15 per unit. Quantity Fixed Variable Total Marginal Average of output Costs Costs Costs Cost Total Cost 0 10 100 20 270 30 100 5 40 440 50 490 60 21 (i) 15 marks Copy the above table to your assignment and complete each column. (ii) 4 marks Using the marginal rule find the profit maximising level of output for this firm. Explain your answer. (iii) 2 marks What is the firm's profit at this level of output? Explain your answer. (iv) 4 marks Explain the relationship between marginal costs and average total cost. (b) 4 marks Differentiate between accounting profit and economic profit. (c) 12 marks Under what circumstances will a competitive firm (i) shut-down and (ii) exit the industry? Illustrate and explain your answers. (d) 4 marks Explain the relationship between marginal product and marginal cost