Buena Manufacturing has sales of £850,000. It used materials of £450,000, direct labour of £175,000 and incurred other variable manufacturing expenses of £30,000. The business also incurred fixed manufacturing expenses of £65,000 and selling and administrative expenses of £40,000. Its opening stock of finished goods was £120,000 and its closing stock had reduced by £25,000.

Calculate each of the:

• cost of production;

• cost of sales;

• contribution margin; 

• operating profit.