In: Economics
Suppose that the market for gourmet deli sandwiches is perfectly competitive and that the supply of workers in this industry is upward-sloping, so that wages increase as industry output increases. Delis in this market face the following total cost: TC = q3 - 15 q2 + 90 q + W where,
Q = number of sandwiches
W = daily wages paid to workers
The wage, which depends on total industry output, equals: W = 0.2 Nq where, N = number of firms.
Assume that the market demand is: QD = 700 - 15 P
1. What is the long-run equilibrium output for each firm?
2. How much does the long-run equilibrium price change as the number of firms increases?
3. What is the long-run equilibrium number of firms?
4. What is the total industry output?
5. What is the long-run equilibrium price?
TC = q3 - 15q2 + 90q + W = q3 - 15q2 + 90q + 0.2Nq
(1)
In long run equilibrium, P = AC = MC.
AC = TC/q = q2 - 15q + 90 + 0.2N
MC = dTC/dq = 3q2 - 30q + 90 + 0.2N
Equating AC and MC,
q2 - 15q + 90 + 0.2N = 3q2 - 30q + 90 + 0.2N
2q2 = 15q
q = 15/2 = 7.5
(2)
P = AC = (7.5)2 - 15 x 7.5 + 90 + 0.2N = 56.25 - 112.5 + 90 + 0.2N = 33.75 + 0.2N
Therefore, as N increases, P increases.
(3)
QD = 700 - 15 x (33.75 + 0.2N) = 700 - 506.25 - 3N = 193.75 - 3N
Market supply (QS) = N x q = N x 7.5
Since QD = QS,
193.75 - 3N = 7.5N
10.5N = 193.75
N = 18.45 ~ 18 firms
(4)
Q = 18 x 7.5 = 135 (Industry output)
(5)
P = 33.75 + 0.2N = 33.75 + 0.2 x 18 = 33.75 + 3.6 = 37.35