EC347 – INDUSTRIAL ORGANISATION ASSIGNMENT Solutions
Hello, dear friend, you can consult us at any time if you have any questions, add WeChat: daixieit
EC347 – INDUSTRIAL ORGANISATION
ASSIGNMENT
Q1.Consider a Cournot duopoly market with demand curve = − , ℎ = 1 + 2 . The firm’s respective marginal costs are 1, 2 . [20 marks]
a) [15 marks] What are the Cournot reaction functions of each firm? What is the Cournot-Nash equilibrium? Illustrate reaction functions and the Cournot-Nash equilibrium in a graph.
b) [5 marks] If firm 2’s marginal cost (2) decreases how does firm 1’s quantity change? Explain why this is the case.
Answer:
a) Firm 1’s profit maximisation problem
1 1 = ( − 1)1 = ( − 1 − 2 − 1)1
1 = 1
− 21 − 2 = 1
Firm 1’s reaction function is 1 = .
Similarly, Firm 2’s reaction function is 2 = .
Solve two reaction functions simultaneously to find the NE.
1 ∗ = and 2 ∗ =
q2
− 1
− 2
2
− 22 + 1
3
0 − 21 + 2 − 1 − 2 q1
3 2
Note. Here we assume that − 1 > and − 2 > so that the NE exists.
b) Note that = >0, thus as firm2’s cost decreases firm1’s equilibrium quantity
decreases. This is because a fall in firm2’s cost means firm 2 will produce more. This will reduce the market price, which reduces firm1’s profit. In order to partially off-set this reduction in profit, firm 1 reduces its output to raise the market price.
Q2.Suppose consumers, each with unit demand, are uniformly distributed along a 1-mile street. Two price-setting firms 1 and 2 are located at each end of the street: firm 1 at 0 and firm 2 at 1. Consumers face a travel cost of £0.1 per mile. Marginal production cost of firm 1 is £0.5 and that of firm 2 is £1.5. Find out the reaction functions and equilibrium prices. [25 marks]
a) [20 marks] Find out the marginal consumer and reaction functions of the firms. Draw reaction functions in a diagram.
b) [5 marks] Determine the equilibrium prices.
Answer:
a) To find the marginal consumer,
1 + 0. 1 × 2 × ∗ = 2 + 0. 1 × 2 × (1 − ∗ )
1 + 0.2∗ = 2 + 0.2(1 − ∗ )
∗ = + (2 − 1)
Since the same number of customers at each point along the line,
1 = ∗ 2 = 1 − ∗
Firm 1’s profit maximisation,
max 1 = (1 − 1) ∗ = (1 − 1)(1 + 5 (2 − 1 ))
= + (2 − 21 ) + = 0
∴ 1 = 2 + : 1′
Firm 2’s profit maximisation,
max 2 = (2 − 3) (1 − ∗ ) = (2 − 3)(1 − 5 (2 − 1)
= − (22 − 1 ) + = 0
∴ 2 = 1 + : 2′
b) Solving two reaction functions, we get the equilibrium prices as
1(∗) = 2(∗) =
Q3.Consider a firm faces two consumers, consumer 1 and consumer 2, with the following two demand curves: P1 = 150 - 6Q1 and P2 = 302 - 4Q2 . The total cost function is () = 6 . [30 marks]
a) [10 marks] If the firm charges different prices to two consumers, what are the profit- maximising prices the firm should charge? Find the profit-maximising level of outputs and profits in each case.
b) [10 marks] The firm decides to use a two-part tariff strategy to maximise its profit. If the firm uses a two-part tariff separately for two consumers, what are the price strategy of the firm and profit in each case?
c) [5 marks] The firm decides to use a single two-part tariff that permits both consumers to buy. Find outputs and price under this scenario. What are profits?
a) [5 marks] The firm has an option of eliminating the low-volume consumer from the market. Would it be better for the firm to focus on the high-volume consumer only? Explain. Find the output, price, and profit if the low-volume consumer is eliminated.
Answer:
a) From the total cost function, AC=MC=6. For consumer 1,
P1 = 150 - 6Q1
MR=MC
150 − 121 = 6
∴ = 12, = 78 = 864
Similarly, For consumer 2,
P2 = 302 - 4Q2
MR=MC
302 − 82 = 6
∴ = 37, = 154 = 5476
b) For consumer 1, if the firm would charge the price of 6 and sell 24 units, the consumer surplus would be = (150 − 6) × 24 × = 1728. Hence the firm will charge a tariff of 1728 and sell 24 units with a price of 6. The profit from consumer 1 is 1728.
For consumer 2, if the firm would charge the price of 6 and sell 74 units, the
consumer surplus would be = (302 − 6) × 74 × = 10,952. Hence the firm will
charge a tariff of 10,952 and sell 74 units with a price of 6. The profit from consumer 2 is 10,952.
The total profit is 12680.
c) If the firm applies the same two-part tariff strategy that permits both consumers to buy, the firm will charge 6 per unit and a tariff of 1728. Hence the profit is = 3456 = 1728 × 2.
d) If the firm focuses only on the high-volume consumer, its profit is maximised with the two-part tariff strategy. Hence the firm will sell 74 units with 6 per unit and charge a tariff of 10,952. Its profits are 10,952.
If the firm uses a two-part tariff separately to consumer 1 and consumer 2, then it would be better to include both consumer 1 and consumer 2. However, if the firm uses the same two-part tariff strategy for both consumers, eliminating the low-volume consumer is better.
Q4. Consider the following game. [25 marks]
|
Firm 2 |
|||
High price |
Middle price |
Low price |
||
Firm 1 |
High price |
40, 40 |
0, 70 |
0, 60 |
Middle price |
70, 0 |
30, 30 |
10, 50 |
|
Low price |
60, 0 |
50, 10 |
20, 20 |
a) [5 marks] This is a one-shot game. Find all the Nash equilibria and explain.
b) [5 marks] Now, this game is repeated for 20 times. What are the sub-game perfect Nash equilibria of this repeated game? Explain your answer.
c) [15 marks] Now, the game is repeated for infinite times. What would be the mechanism to reach any other equilibrium than Q4 b)? Explain in detail.
Answer:
a) For both players, No fight is a dominated strategy. After eliminating the dominated str ategy, the game becomes below.
|
Middle price |
Low price |
Middle price |
30, 30 |
10, 50 |
Low price |
50, 10 |
20, 20 |
Again, Middle price is a dominated strategy and Low price is a dominant strategy for both players. Hence, the unique equilibrium of the stage game is (Low price, Low pric e).
b) Since the stage game is repeated for 20 times, the NE (Low price, Low price) is playe d in each stage.
c) Now the game is repeated for infinite times. You need to mention the following throu gh logic-
a. It may be possible to reach (High price, High price) through trigger strategy.
b. Describe the strategies.
c. Discuss discount rate (or discount factor)
ℎ = ∑ 0 40 =
= 70 + ∑ 1 20 = 70 +
The players will choose the strategy “High price” only if ℎ ≥ Hence, if ≤ 0.6, then both players always stick to the strategy
“High price” .
d. Mention how with sufficiently high patient, High price can be reached.
2022-04-26