An economist calculates that a firm has incurred the following costs over the course of a year: Item Cost ($ 000) Wages and salaries 150 Opportunity cost of owner's time 40 Materials 80 Rent 30 Marketing fees 20 Interest on bank loans 25 Interest foregone on finance provided by owner 15 (a) Differentiate between the concept of costs as viewed by an economist and as viewed by an accountant. [4 marks] (b) By how much does total cost as defined by an economist exceed the total cost as defined by an accountant? [4 marks] (c) If the total revenue of the firm is $355,000, what is the profit of the firm according to: (i) the accountant (ii) the economist? Show your calculations and explain the significance of any difference. [6 marks]