Respuesta :
Answer:
Please find the detailed answer as follows:
Explanation:
1. Under perfect competition model, the profit maximising level of otuput is set where the P = MC
MC = 3 and P = 30 - Q
P = MC
30 - Q = 3.
Q = 27 units.
Thus P = 30 - 27 = $3.
2. Monopoly profit maximising level of output is where the MR = MC
P = 30 - Q
TR = P*Q
TR = (30 - Q)*Q
TR = 30Q - Q2
MR = \deltaTR/\deltaQ
MR = 30 - 2Q
MR = MC
30 - 2Q = 3
27 = 2Q
Q = 13.5 units.
P = 30 - 13.5 = $16.5
3. Under duopoly, Q = Qa + Qb
where Qa and Qb are the output share of firm A and firm B respectively.
Then, P = 30 - Qa - Qb.
for firm A :
TR = P*Q
TR = (30 - Qa - Qb)*Qa
TR = 30Qa - Qa2 - Qa*Qb
MR = \deltaTR/\deltaQa
MR = 30 - 2Qa - Qb
MR = MC
30 -2Qa - Qb = 3
or 27 - 2Qa = Qb..........................equation (i).
For firm B :
TR = P*Q
TR = (30 - Qa - Qb)*Qb
TR = 30Qb - Qa*Qb - Qb2
MR = \deltaTR/\deltaQ
MR = 30 - Qa - 2Qb
MR = MC
30 - Qa - 2Qb = 3
or 27 - 2Qb = Qa...............equation (ii).
substituting the value of equation (i) into equation (ii), we get,
27 - 2(27 - 2Qa) = Qa
27 - 54 + 4Qa = Qa
-27 = -3Qa
Qa = 9 units.
Plugging in this value to get Qb,
27 - 2*9 = Qb
Qb = 9 units.
Q = Qa + Qb = 9 + 9 = 18 units.
P = 30 - 18 = $12.
4. The standard reaction function of firm 2 is given as = a-Cb/2b - 1/2*Qa
P = 30 - (Qa + Qb)
where a= 30 b = 1 and C = 3.
Leader's output = (a + Cb - 2Ca)/2b
Leader's output = (30+3 - 3*2)/2 = 13.5 units.
Reaction function of firm B,
Qb = 30 - 3/2 = 13.5 - 1/2*13.5
Qb = 6.75 units.
P = 30 - (13.5 - 6.75) = $9.75