Correct! First, consider the change in consumer surplus. The original consumer surplus is the area of the triangle bounded by the equilibrium price of $3, the vertical price axis, and the demand curve. This area is (1/2) × (20 million gallons) × ($2) = $20 million. When the price decreases, the quantity supplied decreases. The new consumer surplus is the area bounded by the new price of $2, the vertical price axis, the demand curve, and the new quantity of 10 million. In the figure below, look at the region bounded by $2, $5, f and h. To calculate the area, first look at the rectangle bounded by $2, $4, f and h. This area is $2 times 10 million, or $20 million. The area of the triangle at top is the area bounded by $4, $5 and f. This is (1/2) × (10 million) × $1, or $5 million. Thus, the new consumer surplus is $25 million. We conclude that consumer surplus increased by $5 million.Next, consider the change in producer surplus. The original producer surplus is the area of the triangle bounded by the equilibrium price of $3, the vertical price axis, and the supply curve. This area is (1/2) × (20 million gallons) × ($2) = $20 million. When the price decreases, the quantity supplied decreases. The new producer surplus is the area bounded by the new price of $2, the vertical price axis, the supply curve. In the figure below, look at the region bounded by $1, $2 and h. The area of this triangle is (1/2) × (10 million) × $1, or $5 million. Thus, the new producer surplus is $5 million. We conclude that producer surplus decreased by $15 million.
Incorrect. First, consider the change in consumer surplus. The original consumer surplus is the area of the triangle bounded by the equilibrium price of $3, the vertical price axis, and the demand curve. This area is (1/2) × (20 million gallons) × ($2) = $20 million. When the price decreases, the quantity supplied decreases. The new consumer surplus is the area bounded by the new price of $2, the vertical price axis, the demand curve, and the new quantity of 10 million. In the figure below, look at the region bounded by $2, $5, f and h. To calculate the area, first look at the rectangle bounded by $2, $4, f and h. This area is $2 times 10 million, or $20 million. The area of the triangle at top is the area bounded by $4, $5 and f. This is (1/2) × (10 million) × $1, or $5 million. Thus, the new consumer surplus is $25 million. We conclude that consumer surplus increased by $5 million. Next, consider the change in producer surplus. The original producer surplus is the area of the triangle bounded by the equilibrium price of $3, the vertical price axis, and the supply curve. This area is (1/2) × (20 million gallons) × ($2) = $20 million. When the price decreases, the quantity supplied decreases. The new producer surplus is the area bounded by the new price of $2, the vertical price axis, the supply curve. In the figure below, look at the region bounded by $1, $2 and h. The area of this triangle is (1/2) × (10 million) × $1, or $5 million. Thus, the new producer surplus is $5 million. We conclude that producer surplus decreased by $15 million.