Answer: See attached file
Explanation:
a) At equilibrium, demand equals supply where the price is $6 and quantity traded is 80 units.
Consumer surplus before price ceiling is area of triangle of A6E whose area is (1/2) * (80 - 0) * (14 - 6) = 320
Producer surplus before price ceiling is area of triangle of 26E whose area is (1/2) * (80 - 0) * (6 - 2) = 160
Total surplus before price ceiling = consumer surplus + producer surplus = 320 + 160 = 480
b) At a price of $5 (price ceiling) where demand = 90 units while supply = 60 units causes shortage of 90 - 60 = 30 units in the market.
Consumer surplus after price ceiling is area of triangle A8G + area of rectangle 85DG whose sum is (1/2) * (14 - 8) * (60 - 0) + (60 - 0) * (8 - 5) = 180 + 180 = 360
Producer surplus after price ceiling is area of triangle 5DC whose sum is (1/2) * (60 - 0) * (5 - 2) = 90
Deadweight loss after price ceiling of triangle GDE whose sum is (1/2) * (80 - 60) * (8 - 5) = 30
Total surplus is consumer surplus + producer surplus after price ceiling = 360 + 90 = 450
