In: Economics
Consider the following market game: An incumbent firm, called firm 3, is already in an industry.
Two potential entrants, called firms 1 and 2, can each enter the industry by paying the entry cost of 2. First, firm 1 decides whether to enter or not. Then, after observing firm 1's choice, firm 2 decides whether to enter or not. Every firm, including firm 3, observes the choices of firms 1 and 2.
After this, all of the firms in the industry (including firm 3) compete in a Cournot oligopoly, where they simultaneously and independently select quantities. The price is determined by the inverse demand curve p = 12-Q, where Q is the total quantity produced in the industry. Firm 3's total cost is c3(q3) = q3. The total cost of the entering firm i is given by ci(qi) = 6.3qi where i can be 1 or 2. (Remember that firms 1 and 2 have to pay the fixed cost of 2 to enter and that neither firm 1 or firm 2 might enter.)
What is the total quantity produced in the market?
Expert Answer
Solution:
Firms demand curve, p=12-Q, where Q = q1+q2+q3
Given TC of firm 3, TC3= c3(q3) =q3
Ci(qi) =6.3qi, i= 1 or 2
P=12-(q1+q2+q3)
=12-q1-q2-q3
Firm 3, TR3 = p.q3
(12-q1-q2-q3)q3
=12q3-q1q3-q2q3-q32
MR3= 12-q1-q2-2q3
TC3= C3(q3)=q3
MC= d/dq3= 1
We know MR=MC,
12-q1-q2-2q3=1
=-q1-q2-2q3=1-12
= q1+q2+2q3=11 ---------------------- eqn (1)
Now let i=1
Firm 1, C1(q1)=6.3 q1+ 2 ( where 2 is the fixed cost)
MC=6.3
TR1=p.q1
=12q1-q12-q2q1-q3q1
MR1= 12-2q1-q2-q3
MR1=MC1
=12-2q1-q2-q3=6.3
=-2q1-q2-q3=6.3-12
=2q1+q2+q3=5.7-------------------------------eqn (2)
Firm 2, i=2
C2(q2)=6.3 q2+2, where 2 is the fixed cost
MC2= d/dq2=6.3
TR2= p.q2
=(12-q1-q2-q3)q2
=12q2-q1q2-q22-q3
MR2= 12-q1-2q2-q3
MR2=MC2
=12-q1-2q2-q3=6.3
=-q1-2q2-q3=6.3-12
=q1+2q2+q3=5.7----------------------------------eqn (3)
Now, solving equation 1 and 2
q1+q2+2q3=11
2q1+q2+q3=5.7 (subtracting)
-q1 +q3=5.3-----------------------------------eqn (4)
Again solving eqn 1 and 3
q1+q2+2q3=11
q1+2q2+q3=5.7 (subtracting)
-q2+q3=5.3-----------------------------------eqn(5)
Now, solving equation 2 and 3
2q1+q2+q3=5.7
q1+2q2+q3=5.7 (subtracting)
q1-q2 = 0
q1=q2-----------------------------eqn (6)
putting eqn (6) in eqn(4)
-q1+q3=5.3------------------------------eqn(7)
Solving equation 7 and 5
q2+q3=5.3
-q2+q3=5.3
2q3=10.6
q3=10.6/2 = 5.3
q3=5.3
q2=5.3-5.3=0
q2=q1=0
Therefore =, the total quantity produced in the market is q1=0,q2=0q3=5.3
Q= 0+0+5.3=5.3