Answer
Total surplus: 800
Consumer surplus: 400
Work Step by Step
Total surplus is triangle ABC and its area can be given by 0.5 $\times$ 20 $\times$ (85-5) = 800
Consumer surplus in this case would be the top half of the total surplus, as the price is at equilibrium, and the difference between the maximum price that consumers are willing to pay and the price they actually pay is the area bounded by the demand curve and a horizontal line drawn from the price axis to the equilibrium price.
Therefore, 800 $\div$ 2 = 400
