Total Variable cost: variable cost per unit x total output or quantity. Total cost=fixed cost + variable cost Marginal cost= change in total cost / change in quantity Average cost= total cost/total output or quantity. Total revenue or total sales revenue=price x quantity sold Marginal revenue=change in total revenue / change in output sold Average revenue= total revenue / total output Example: T.V manufacturer costs and revenue. Calculate the costs, revenues and break even. Break-even output=fixed cost/contribution. Where contribution = selling price - variable cost per unit. Selling price of T.V= $800 Variable cost per T. V =$200 Quantity Fixed Variable Marginal Marginal Total cost Total variable cost Total revenue cost cost/unit cost revenue 0 $10,000 0 0 S 10 15 20 25 30