AP Microeconomics, AP exams

Unit 1: Basic Economic Concepts

Unit 1 introduces scarcity, opportunity cost, the production possibilities curve, and comparative advantage. It also establishes marginal analysis as the decision rule the rest of the course applies. The concepts are shared with AP Macroeconomics, but the applications quickly diverge.

Position: 1 of 6 units
Topics covered: 5 topics in this guide

What is covered

Topics inside this unit.

These topics describe the scope students most often review for this part of AP Microeconomics. Treat them as a study checklist rather than an exhaustive list of what a single exam form can sample.

Scarcity and opportunity cost: Limited resources against unlimited wants, and cost measured as the value of the next best alternative forgone.
Economic systems and resource allocation: How different systems answer what, how, and for whom to produce, and the role of prices as signals.
The production possibilities curve: Efficiency and attainability, increasing opportunity cost from resource specialization, and shifts from growth.
Comparative advantage and gains from trade: Calculating opportunity cost per unit and identifying terms of trade that benefit both parties.
Marginal analysis and consumer choice: Comparing marginal benefit with marginal cost, diminishing marginal utility, and the utility-maximizing rule.

Study tips

How to practice Basic Concepts.

Section-specific guidance that follows from how this material is usually tested.

Practice the utility-maximizing rule numerically, since it appears in short free-response prompts.
Learn to compute comparative advantage both per unit of output and per unit of input.
Treat marginal analysis as the default reasoning tool for the entire course, not a Unit 1 topic.

Where this fits

Unit 1: Basic Economic Concepts is 1 of 6 units in the AP Microeconomics guide. Use the full guide to balance it against everything else you have to review.

Back to the AP Microeconomics guide Official exam information

Sample Basic Concepts questions

Practice questions, not yet expert-reviewed

Original practice questions written to the published framework for this section. No expert has reviewed them, and they are not taken from any official exam. Try each one before you open the answer.

Question 1Foundational
What does the law of diminishing marginal utility state about additional units of a good consumed in a given period?
1. AEach additional unit adds less satisfaction than the unit before it
2. BEach additional unit reduces the consumer's total satisfaction
3. CEach additional unit costs the producer more to make
4. DConsumers always gain equal satisfaction from every unit
Show answer
Answer: A. Each additional unit adds less satisfaction than the unit before it
Marginal utility falls as consumption rises, which is why the third slice of pizza is worth less to you than the first. Saying total satisfaction falls is the tempting distractor, but total utility keeps rising as long as marginal utility is positive; it only declines once marginal utility turns negative.
Key insight: Diminishing marginal utility is why demand curves slope downward: buyers will pay less for each additional unit.
Question 2Foundational
A production possibilities curve is drawn bowed outward from the origin rather than as a straight line. What does that shape indicate?
1. AOpportunity cost increases as more of one good is produced
2. BOpportunity cost stays constant along the entire curve
3. CResources are equally well suited to producing either good
4. DThe economy is currently using its resources inefficiently
Show answer
Answer: A. Opportunity cost increases as more of one good is produced
A bowed curve reflects resources that are specialized, so expanding one good forces the economy to move progressively less suitable resources into it and give up ever more of the other good. Constant opportunity cost is the tempting distractor, but that produces a straight-line frontier, which assumes resources are perfectly adaptable between the two goods.
Key insight: Straight-line frontiers mean interchangeable resources; bowed frontiers mean specialized ones.
Question 3Intermediate
A consumer spends all income on two goods. The next unit of Good X costs 2 dollars and yields 20 utils, while the next unit of Good Y costs 5 dollars and yields 40 utils. What should the consumer do to raise total utility?
1. ABuy more of Good X and less of Good Y
2. BBuy more of Good Y and less of Good X
3. CKeep the current combination, which already maximizes utility
4. DBuy more of both goods
Show answer
Answer: A. Buy more of Good X and less of Good Y
Good X delivers 10 utils per dollar while Good Y delivers only 8, so moving a dollar from Y to X raises total utility. Choosing Good Y is the tempting distractor because it yields more utils per unit, but the utility-maximizing rule compares utility per dollar spent, not utility per unit.
Key insight: Equalize marginal utility per dollar across all goods; whichever good has the higher ratio deserves the next dollar.
Question 4Intermediate
On one acre of land Farm A can grow 30 bushels of corn or 10 bushels of soybeans, and Farm B can grow 20 bushels of corn or 10 bushels of soybeans. Which farm has the comparative advantage in soybeans?
1. AFarm B
2. BFarm A
3. CBoth farms equally
4. DNeither farm
Show answer
Answer: A. Farm B
Each bushel of soybeans costs Farm A three bushels of corn but costs Farm B only two, so Farm B sacrifices less to grow soybeans. Farm A is the tempting distractor because it produces more corn per acre and looks more productive overall, but absolute advantage in corn tells you nothing about which farm gives up less to grow soybeans.
Key insight: Comparative advantage is about what a producer gives up, so always convert the table into opportunity cost per unit before answering.
Question 5Advanced
Producing one unit of cloth costs Country A three units of grain and costs Country B one unit of grain. Which terms of trade would make both countries better off by trading cloth for grain?
1. A2 units of grain per unit of cloth
2. B0.5 units of grain per unit of cloth
3. C1 unit of grain per unit of cloth
4. D3.5 units of grain per unit of cloth
Show answer
Answer: A. 2 units of grain per unit of cloth
Country B will export cloth only if it receives more than the one unit of grain it sacrifices, and Country A will import cloth only if it pays less than the three units it would give up producing cloth itself, so any rate strictly between one and three works. The rate of exactly 1 is the tempting distractor because it sits at the edge of the range, but at that price Country B gains nothing from trading rather than producing grain itself.
Key insight: Mutually beneficial terms of trade always lie strictly between the two producers' opportunity costs.

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Unit 1: Basic Economic Concepts