Answer: Derive equilibrium before subsidy:
At equilibrium: Qd = Qs
100 – 10P = 10P
100 = 10P + 10P
100 = 20P
P = 5
Equilibrium price = 5
Substitute in the demand function to derive equilibrium quantity:
Q = 100 – 10P
Q = 100 – 10(5) = 100 – 50 = 50
Q = 50
Equilibrium quantity = 50
Consumer surplus = ½ x 50 x (10 – 5) = 125
Producer surplus = ½ x 50 x (50 – 0) = 125
Derive new equilibrium after subsidy:
First calculate the new Qs function:
Qs = 10P
Qs = 10 (P + 1)
Qs = 10P + 1
Set: Qd = Qs
100 – 10P = 10P + 1
100 – 1 = 10P + 10P
99 = 20P
P = 4.95
New equilibrium price = 4.95
Substitute in either the demand or supply function to derive the equilibrium quantity:
Qs = 10P + 1
Qs = 10(4.95) + 1
Q = 49.5 + 1 = 50.5
New equilibrium quantity = 50.5
The effects of the subsidy are as follows:
Consumer surplus gain = ½
×
× (5 – 4.95)
×
× (50.5 – 50) + 50
×
× (5 – 4.95) = 0.025 + 2.5 = 2.525
Producer surplus gain = ½
×
× (5.95 – 5)
×
× (50.5 – 50) + 50
×
× (5.95 – 5) = 0.2375 + 47.5 = 47.7375
Government subsidy cost = 50.5
×
× 1 = 50.5
Welfare = Total Benefit – Total Cost
Total benefit = CS + PS = 2.525 + 47.7375 = 50.265
Total Cost = 50.5
Welfare = 50.265 – 50.5 = -0.2375
Deadweight Loss = -0.2375
i know it makes no sense but this is what i got.