In: Economics
You are the manager of a company that sells iPhone cases. The costs of producing the cases are given by C = 200 + 20Q (or the fixed costs are $200 and the variable costs are $20 per case). The demand for the cases is given by QD = 180 – 5P.
a) What is the firm’s optimal quantity and price?
b) What is the firm’s profit at the optimal quantity and price?
c) If the fixed costs decrease from $200 to $100, what is the new optimal price and quantity? What is the firm’s new profit?
d) If the variable costs increase from $20/unit to $24/unit, what is the new optimal price and quantity? What is the firm’s new profit?
Answer : Firm optimal price and quantity has been determining as follows :
C=200+20Q
MC=20
Q=180-5P
5P=180-Q
P= 36-Q/5
PQ=36Q-Q 2/5
MR= 36-2Q/5
Profit Maximisation level
MR=MC
36-2Q/5= 20
36-20= 2Q/5
16= 2Q/5
2Q=80
Q=40units
P= 36-Q/5= 36-8=$28
b : Firm profit =TR-TC
Firm profit = 36Q-Q 2/5 - 200-20Q = 16Q-Q 2/5 -200
16(40)-((40)2/5)-200= $120
c : Fixed cost decrease $200 to $100 than effect is
TR = 36Q -Q 2 /5
MR=36-2Q/5
C= 100+20Q
MC= 20
Therefore optiumal price is $28 and optiumal Quantity is 40 units.
Firms new profit=TR-TC= 16Q-Q 2/5 -100= $220
d : Variable cost increase it means
C= 200+24Q
MC=24
MR= 36-2Q/5
MR=MC
36-2Q/5=24
36-24=2Q/5
12= 2Q/5
Q= 30 units
P= 36-Q/5 = 36-(30/5)= $30
Profit = 36Q-Q 2/5 - 200-24Q
Profit = 12Q-Q2/5-200= $360-$380=($20)
Loss of $20 when variable cost increases from $20 to $24 and fixed cost remains the same.