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1. You are given the following data for your firm, which sells high-capacity vid

ID: 1117547 • Letter: 1

Question

1.   You are given the following data for your firm, which sells high-capacity video MP3 players.

Q

P

TC

0

$1,000

$1,500

2

$960

$2,568

4

$920

$3,660

6

$880

$4,824

8

$840

$6,108

10

$800

$7,560

12

$760

$9,228

14

$720

$11,160

16

$680

$13,404

18

$640

$16,008

20

$600

$19,020

a.   Determine equations for P=f(Q), MR=f(Q), ATC=f(Q, Q2), AVC=f(Q, Q2), MC=f(Q, Q2). Recall that your marginal equations should be derivatives of your totals!

b.   Determine the profit-maximizing price and quantity. (Since MC is in terms of Q2, solving with calculus and algebra can be messy. Your table should give an exact answer.)

c.   How much total profit would your firm earn if you set P and Q according to part b?

d.   Describe the competitiveness of the market by calculating the Lerner index.

Q

P

TC

0

$1,000

$1,500

2

$960

$2,568

4

$920

$3,660

6

$880

$4,824

8

$840

$6,108

10

$800

$7,560

12

$760

$9,228

14

$720

$11,160

16

$680

$13,404

18

$640

$16,008

20

$600

$19,020

Explanation / Answer

a.   Determine equations for P=f(Q), MR=f(Q), ATC=f(Q, Q2), AVC=f(Q, Q2), MC=f(Q, Q2). Recall that your marginal equations should be derivatives of your totals!

From the table, we figure out that fixed cost is $1500. Total cost TC = Q^3 - 3*Q^2 + 536Q + 1500.

Total variable cost = Q^3 - 3*Q^2 + 536Q. MC = 3Q^2 - 6Q + 536. AVC = TVC/Q = Q^2 - 3Q + 536. ATC = TC/Q = Q^2 - 3Q + 536 + 1500.

Price P = 1000 - 20Q. MR = 1000 - 40Q.

b.   Determine the profit-maximizing price and quantity.

Note that MR = 1000 - 40Q and MC = 3Q^2 - 6Q + 536. We have

3Q^2 - 6Q + 536 = 1000 - 40Q

3Q^2 + 34Q - 464 = 0

This is a quadratic equation which solves for Q = 8

Price = 1000 - 8*20 = $840

c.   How much total profit would your firm earn if you set P and Q according to part b?

Profit = 840*8 - (8^3 - 3*8^2 + 536*8 + 1500) = 612

d.   Describe the competitiveness of the market by calculating the Lerner index

Price = 840, MC = 3*8^2 - 6*8 + 536 = 680

Lerner index = (840 - 680)/840 = 0.19

Market is highly competitive as lerner index is close to zero.