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Exam III Review. Econ 101 – 1 Tuesday, November 28 th. Value of Total Product (VTP): VTP = Q*P = P*TP Value of Average Product (VAP): How much revenue does each person produce, on average? Value of Marginal Product (VMP) How much revenue does the last person hired produce?. The Short-Run.
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Exam III Review Econ 101 – 1 Tuesday, November 28th Sherman
Value of Total Product (VTP): VTP = Q*P = P*TP Value of Average Product (VAP): How much revenue does each person produce, on average? Value of Marginal Product (VMP) How much revenue does the last person hired produce? The Short-Run Sherman
The Short-Run:AP • How much average does each person produce, on average, when: • Labor = 1? • Labor = 2? • Labor = 3? Sherman
The Short-Run:AP • AP when: • L = 1: • AP = TP/L • AP = 80/1 • AP = 80 • L = 2: • AP = 200/2 • AP = 100 • L = 3: • AP = 270/3 • AP = 90 Sherman
The Short-Run:VAP • Price = $3 • What is the VAP when: • Labor = 1? • L = 2? • L = 3? Sherman
The Short-Run:VAP • Price = $3 • VAP when: • L = 1 • VAP = AP*P • VAP = 80*3 • VAP = $240 • L = 2 • VAP = 100*3 • VAP = $300 • L = 3 • VAP = 90*3 • VAP = $270 Sherman
The Short-Run:Marginal Product • How much more is produced with the addition of the: • 1st person? • 2nd person? • 3rd person? Sherman
The Short-Run:Marginal Product • Marginal Product of: • 1st person • MP1 = (TP1 – TP0)/ΔL • MP1 = (80 – 0)/1 • MP1 = 80 • 2nd person • MP2 = (TP2 – TP1)/ΔL • MP2 = (200 – 80)/1 • MP2 = 120 • 3rd person? • MP3 = (TP3 – TP2)/ΔL • MP3 = (270 – 200)/1 • MP3 = 70 Sherman
The Short-Run:Value of Marginal Product • How much more revenue is produced with the addition of the: • 1st person? • 2nd person? • 3rd person? Sherman
The Short-Run:Value of Marginal Product • Price = $3 • VMP when we add the: • 1st person • VMP = MP*P • VMP = 80*3 • VMP = $240 • 2nd person • VMP = 120*3 • VMP = 360 • 3rd person • VMP = 70*3 • VMP = $210 Sherman
What can the firm vary in the short run? Capital: is it quick/easy/cheap to build new buildings? buy machinery? Labor: is it easy to hire/fire people in the short run? How does the firm decide how much labor to use? The Short Run:Choosing Inputs Sherman
The Short Run:Choosing Labor • The firm will only hire if the last person pays for herself (VMP >= Wage) • How does the firm decide how much labor to use? • VMP = cost of last employee (wage) • Where does this firm stop? Sherman
As quantity produced rises: diminishing marginal returns “too many chefs in the kitchen spoil the broth” gains to specialization decrease increasing marginal costs Profit is maximized where P = MP The Short Run:Cost Curves and Revenue Sherman
Individual firms and consumers cannot affect supply, demand, or price. Firms have identical products, information, and production technologies Free entry and exit The Short Run:Perfect Competition Sherman
Total Profit = Total Revenue – Total Cost Π = TR – TC (Q/Q)*Π = (TR – TC)*(Q/Q) Π = (TR/Q – TC/Q)*Q Π = (P*Q/Q – TC/Q)*Q Π = (P – ATC)*Q Economic Profit Sherman
Is the economic profit here positive, negative, or zero? The Short Run:Enter/Exit Decisions S P P MC ATC P0 P0 D q 100 1000 Q Sherman
Π > 0 Who will want to enter the market? Who will want to exit? The Short Run:Enter/Exit Decisions S P P MC ATC P0 P0 D q 100 1000 Q Sherman
Set q where P = MC Who will enter? exit? The Short Run:Enter/Exit Decisions S P P MC ATC P1 P1 D q 100 1000 Q Sherman
Π = 0 Who will want to enter the market? Who will want to exit? The Short Run:Enter/Exit Decisions P P MC S ATC Pe Pe D qe q Qe Q Sherman
Π = 0 This is the long-run equilibrium! No one enters, no one exits. P = MC = ATC The Short Run:Enter/Exit Decisions P P MC S ATC Pe Pe D qe q Qe Q Sherman
The Long Run:Increasing Returns to Scale Remember: ATC = TC/Q P LRAC ATC0 P = ATC0 ATC1 P = ATC1 Q Sherman
The Long Run:Constant Returns to Scale Remember: ATC = TC/Q P LRAC ATC2 ATC3 P = ATC2,3 Q Sherman
The Long Run:Decreasing Returns to Scale Remember: ATC = TC/Q P LRAC ATC5 P = ATC5 ATC4 P = ATC5 Q Sherman