Week 6 · Quiz

Week 6 — Quiz · Consumer & Producer Surplus & Efficiency

Principles of Microeconomics · ECON 1 Fall 2026 · Prof. Kessler Fictional sample

Course: Principles of Microeconomics (ECON 1) · Silver Oak University (fictional sample) · Prof. Kessler
Objective 4 · 10 questions · 10 points · closed to AI · one attempt
Auto-graded (Classic QTI): see F-quiz-week-06-qti.xml for the Canvas import. Every numeric answer is pre-computed; every surplus/curve claim is verified.

The questions (human-readable; answer key below)

Q1. Consumer surplus is best defined as —
A) The area above the supply curve and below the price B) The total amount buyers spend in a market C) The area under the demand curve and above the market price D) The seller's gain from a transaction

Q2. Producer surplus is best defined as —
A) The area above the supply curve and below the market price B) The amount a producer spends on inputs C) The area under the demand curve and above the price D) Total market revenue

Q3. In the market shown (demand P = 20 − 0.5Q, supply P = 4 + 0.5Q), what is the equilibrium quantity Q* and price P*?
A) Q* = 8, P* = 16 B) Q* = 12, P* = 14 C) Q* = 16, P* = 12 D) Q* = 20, P* = 10

Q4. Using Q* = 16 and P* = 12 for the market above (demand intercept = 20), consumer surplus equals —
A) 48 B) 128 C) 32 D) 64

Q5. For the same market (supply intercept = 4, P* = 12, Q* = 16), producer surplus equals —
A) 32 B) 48 C) 64 D) 128

Q6. The "total surplus" at equilibrium in this market is —
A) 64 B) 32 C) 128 D) 96

Q7. (Select all that apply.) Which of the following statements about the competitive equilibrium are TRUE?
☑ A) It maximizes total surplus ☑ B) It is allocatively efficient ☐ C) It necessarily produces an equal split of CS and PS ☐ D) It guarantees fairness in distribution

Q8. (True/False) If a price is forced ABOVE the market equilibrium, consumer surplus RISES while producer surplus falls. → False

Q9. (Matching) Consumer surplus → Area under demand, above price; Producer surplus → Area above supply, below price; Total surplus → CS + PS; maximized at the competitive equilibrium; Deadweight loss → Reduction in total surplus when price is forced off equilibrium. (Distractor: "Area under supply, below price.")

Q10. In a different market, demand is P = 24 − Q and supply is P = 6 + 0.5Q, giving equilibrium Q* = 12 and P* = 12. Consumer surplus equals —
A) 36 B) 72 C) 108 D) 144

Answer key & feedback (instructor)

Q	Type	Answer	Feedback (the idea)
1	MC	C	CS is the buyers' bonus — the triangle UNDER demand and ABOVE the price line. PS is the sellers' side.
2	MC	A	PS is ABOVE supply and BELOW price — the sellers' surplus. Confusing it with revenue is a classic trap.
3	MC	C	Set 20 − 0.5Q = 4 + 0.5Q → Q = 16, P = 12. Both verified.
4	MC	D	CS = ½ × 16 × (20 − 12) = ½ × 16 × 8 = 64. Don't forget the ½.
5	MC	C	PS = ½ × 16 × (12 − 4) = ½ × 16 × 8 = 64.
6	MC	C	TS = CS + PS = 64 + 64 = 128.
7	MA	A, B	The equal-split and "fairness" claims are false. Equal CS = PS is a coincidence of equal slopes here, not a general fact. Efficiency is positive; fairness is normative.
8	TF	False	A price ABOVE equilibrium reduces quantity traded — fewer buyers can transact, so CS FALLS (buyers lose part of their triangle).
9	Match	as above	The distractor ("area under supply, below price") describes no standard surplus concept — it's a trap for CS/PS confusers.
10	MC	B	Fresh market: 24 − Q = 6 + 0.5Q → Q* = 12, P* = 12; CS = ½ × 12 × (24 − 12) = ½ × 12 × 12 = 72. (Distractors: 36 = PS, 108 = total surplus, 144 = forgetting the ½.)

Quality gate (self-checked): Q3 equilibrium (20 − 0.5Q = 4 + 0.5Q → Q=16, P=12) re-computed ✓; Q4 CS = ½×16×8 = 64 ✓; Q5 PS = ½×16×8 = 64 ✓; Q6 TS = 128 ✓; Q10 fresh-market equilibrium (24 − Q = 6 + 0.5Q → Q=12, P=12) and CS = ½×12×12 = 72 re-computed ✓; surplus areas (CS above P below demand; PS below P above supply) verified ✓; distractors target the named traps (CS vs PS flip; forgetting ½; efficiency ≠ fairness; equal-split is not universal). No free numeric entry. (Note: surplus computations are kept at the equilibrium where the triangle formula is exact; binding price controls and their rationing are treated in Week 7.)

This is the human-readable quiz with its vetted answer key and rationale. The import-ready Classic-QTI version (F-quiz-week-06-qti.xml) ships inside the course's .imscc package — it lands in the Canvas gradebook on import.

~ Prof. Kessler's edition · Fall 2026 · built with thecoursemaker.com