1. Chapter The Costs of Production 13

2. What Does a Firm Do? Firm’s Objective – Firms seek to maximize profits Profits = Total Revenues minus Total Costs Choose Q such that Max {TR(Q*) –TC{Q*} Total revenue – Revenue received fromsale of its output Total cost – Market value of the inputs a firm uses in production 2

3. Why Are Costs Important to a Firm? Primary economic objective of a firm – Maximize profits Total revenues depend on customer demand Tot Rev(Q) = Price(Qd) x Qd – Price-taker (competitive world) » Initially assume: firm is a Price-taker (competitive world) » Competitors numerous and perfect substitutes » Demand is perfectly elastic » Tot Rev is not controllable by firm Costs {can controlled by p-taking firm} – Depend on amount supplied (Q*) by the firm – prices of and amounts used of inputs 3

4. What are Costs? Costs as opportunity costs – Explicit costs Input costs that require an outlay of money by the firm Reflect value of input used by other producers/markets – price willing to pay – Implicit costs Input costs that do not require an outlay of money by the firm Opportunity costs of time; alternative investment 4

5. Table A production function and total cost: Caroline’s cookie factory 1 5 Number of workers Output (quantity of cookies produced per hour) Marginal product of labor Cost of factory Cost of workers Total cost of inputs (cost of factory + cost of workers) 01234560123456 0 50 90 120 140 150 155 $30 30 $0 10 20 30 40 50 60 $30 40 50 60 70 80 90 50 40 30 20 10 5

6. Figure Total Cost 50 40 30 20 10 80 70 60 $90 Quantity of Output (cookies per hour) 100 80 60 40 20 160 140 120 Caroline’s production function and total-cost curve 2 6 (a) Production function The production function in panel (a) shows the relationship between the number of workers hired and the quantity of output produced. Here the number of workers hired (on the horizontal axis) is from the first column in Table 1, and the quantity of output produced (on the vertical axis) is from the second column. The production function gets flatter as the number of workers increases, which reflects diminishing marginal product. The total-cost curve in panel (b) shows the relationship between the quantity of output produced and total cost of production. Here the quantity of output produced (on the horizontal axis) is from the second column in Table 1, and the total cost (on the vertical axis) is from the sixth column. The total-cost curve gets steeper as the quantity of output increases because of diminishing marginal product. (b) Total-cost curve Number of Workers Hired 0 123456 Production function Total-cost curve Quantity of Output (cookies per hour) 0 20406080100120140160