Question 4 ([2 + 2 + 2 + 2 + 2 + 2] + 4 = 16 marks) Part (A) A company had the following results for this year: Sales (15 000 units) Variable expenses Fixed expenses Net profit $300 000 180 000 80 000 $40 000 Required: (a) Calculate the contribution margin in dollars (b) Calculate the contribution margin ratio (c) Calculate the breakeven sales in dollars. (d) Calculate the breakeven sales in units. (e) Calculate how many additional units to be sold to increase net profit from $40,000 to $100,000 (f) Explain the concept of the 'relevant range' relating to cost-volume-profit analysis