VTR Ltd. wants you to examine the effect of changes in sales on their income before tax. The costs that the company incurred last year are as follows: Fixed costs: Depreciation R 2 000 000 Plant maintenance R340 000 Salaries R 800 DOO Office expense R 400 000 Advertising R60 000 Interest on debt R 400 000 Total R 4 000 000 Variable cost per unit output: Labour R 160 Materials R 120 Total R 280 Assume that VTR sells its products at R 800 per unit 1 Calculate the oreak even volume of sales. (4) 2. Tabulate the variable cost sales pre-tax income and net income of Zebra when they produce and sell 50 000 100 000, 200 000 and 300 000 units. The tax rate is 30%. (4) 3 Illustrate the variables in b) by means of a graph (5) 4 Explain the difference between fixed costs and variable costs (2)