Economics Questions Answered, One Page Each

A commodity such as wheat or a farmers market selling identical produce is close to perfect competition, and a local water utility or a patented drug is close to a monopoly. Place a real firm by counting sellers, checking whether the product is identical, and measuring entry barriers.

A monopoly is a single firm with no competitors, while a cartel is a group of competing firms that agree to act like one firm by fixing prices or output. That agreement is the whole difference, and it is also why cartels tend to fall apart as individual members cheat on it.

Find a Nash equilibrium by checking every cell of a payoff matrix: if either player would rather switch given what the other player picked, that cell is not the equilibrium. A Nash equilibrium is a combination of choices where no player can do better by changing only their own choice.

Find the quantity where marginal revenue equals marginal cost, then compare price to average total cost there: price above ATC means profit, equal means break even, below means a loss. A flat demand curve marks a price taking firm; a downward sloping one marks a firm with market power.

A monopoly produces less output and charges a higher price than a perfectly competitive market serving the same demand, because the monopolist sets marginal revenue equal to marginal cost while price sits above marginal revenue; the surplus lost on the units not produced is deadweight loss.

A production possibilities curve rests on four assumptions: two goods, a fixed quantity of resources, fixed technology, and full and efficient use of those resources, plus a fixed time period; each one strips out real-world detail so one graph can show the tradeoff between two outputs.

Eating past full at a buffet because you paid, staying in a long line because of the time already spent, and funding a failing project because of past spending are all examples. In each, money or time that is gone for good steers a choice that only future costs and benefits should decide.

In a surplus the price falls. As it falls, quantity demanded rises along the demand curve and quantity supplied falls along the supply curve until the two are equal at equilibrium. Neither curve shifts during this adjustment; only the quantities change.

When gas prices rise, drivers buy fewer gallons. When a cafe raises a latte from 5 to 6 dollars, it sells fewer lattes. When a coat goes on sale, more coats sell. Each shows the law of demand: a higher price lowers quantity demanded, a move along the curve, not a fall in demand.

Overfished ocean stocks, an aquifer drained by many wells, shared grazing land, a free highway at rush hour, greenhouse gas emissions into the shared atmosphere, and overuse of antibiotics are all examples. Each resource is rival and non-excludable, so users take more than is best for the group.

A natural monopoly graph shows an average total cost curve that is still falling where it crosses demand, with marginal cost below it. It marks three outcomes: the unregulated price where MR = MC, the fair-return price where P = ATC, and the socially optimal price where P = MC, which causes a loss.

It shows the marginal social cost curve (MSC) above the private supply curve (MPC), so the market produces where demand meets MPC, a larger quantity than the social optimum where demand meets MSC. The overproduced units form a deadweight loss triangle pointing back toward the optimum.

A per-unit subsidy to producers shifts the supply curve down (to the right) by the amount of the subsidy. Quantity rises, buyers pay less, sellers receive more, the government pays subsidy times quantity, and a deadweight loss triangle appears between the old and new quantity.

Diminishing marginal returns begins where the marginal product curve peaks and starts falling. On the total product curve, that is where total product keeps rising but at a slower rate, so the curve bends from getting steeper to getting flatter. Marginal cost starts rising at the same output.

P = MC means price equals marginal cost: what buyers pay for the last unit equals the cost of making it. That is the allocative efficiency condition, and for a perfectly competitive firm it is also the profit-maximizing rule, since P = MR. P > MC usually signals market power and too little output.

The total cost curve starts on the vertical axis at total fixed cost, then rises with output: at a decreasing rate at first while marginal cost falls, then at an increasing rate once diminishing marginal returns push marginal cost up. It is the total variable cost curve shifted up by fixed cost.

Example: at a farmers market, shoppers want 400 pounds of strawberries at 4 dollars a pound and growers bring exactly 400 pounds at that price. That price and quantity are the market equilibrium: quantity demanded equals quantity supplied, so no shortage or surplus pushes the price to change.

Third-degree price discrimination is charging identifiable groups of buyers different prices for the same good, based on how price sensitive each group is. The firm sets marginal revenue equal to marginal cost in each group, so the more elastic group, such as students, pays less.

The current account records trade in goods and services, income, and transfers, while the capital and financial account records purchases and sales of assets; money entering a country is a credit, money leaving is a debit, and the two accounts sum to roughly zero.

Saving, taxes, and imports are the three leakages that pull money out of the circular flow. Investment, government spending, and exports are the matching injections that put it back in, and equilibrium requires the two totals to be equal.

That point is equilibrium, specifically the equilibrium level of real GDP in the circular flow model: the output level where saving plus taxes plus imports (total leakages) equals investment plus government spending plus exports (total injections).

Households sell labor in the resource market, also called the factor market, where households supply labor, land, capital, and entrepreneurship to firms in exchange for wages, rent, interest, and profit.

Money is the payment for the goods and factors moving the other way. Households pay firms for output in the product market, and firms pay households for labor and other inputs in the factor market, so every real flow has a matching money flow running backward.

Long-run economic growth is shown by the long-run aggregate supply (LRAS) curve shifting right, usually with short-run aggregate supply, as potential output rises. An AD shift alone is not long-run growth, so on a multiple-choice graph pick the one where LRAS shifts right.

The main macroeconomic objectives are economic growth (rising real GDP), low unemployment (near the natural rate), and price stability (low, steady inflation). Broader lists add a sustainable balance of payments and a fair distribution of income.

A new tank bought by the military counts as government purchases (G) in the expenditure approach, GDP = C + I + G + NX. It is a newly produced final good bought by government, so its price adds to G. If the tank was built abroad, imports rise by the same amount and GDP does not change.

Yes, through trade. A country can never produce past its own production possibilities curve, but specializing in the good where it holds a comparative advantage and trading for the other good lets it consume a bundle that sits outside that curve.

A market economy relies only on prices and private decisions to answer what, how, and for whom to produce, while a mixed economy keeps that market core but adds government action such as public goods, regulation, and transfers. Every real economy in operation today is mixed to some degree.

The three basic economic questions are what to produce, how to produce it, and for whom to produce it. Every economy, whether market, command, or mixed, has to answer all three because scarce resources can never satisfy every want, so someone has to choose.

A production possibilities curve shows three things: scarcity, since it sits on a fixed frontier for two goods; opportunity cost, read as the slope between two points; and efficiency, since only points on the curve use every resource fully. A shifting curve adds growth.

A point inside the production possibilities curve represents an inefficient use of resources: the economy is producing less of both goods than it could, usually because of unemployment or idle capital. A point on the curve is efficient; a point outside it is currently unattainable.

PPC stands for production possibilities curve, also called the production possibilities frontier. It is the graph showing the maximum combinations of two goods an economy can produce when every resource is fully and efficiently employed.

The circular flow model shows how households and firms exchange goods, services, resources, and money. The fuller version adds the government and the rest of the world, moving through the product market and the factor market.

A change in the quantity or quality of resources, or a change in technology, shifts the whole production possibilities curve: outward for economic growth, inward for a loss of resources. A PPC showing economic growth shifts outward, away from the origin.

The producer with the lower opportunity cost for that good has the comparative advantage, not the one who can make more of it. To answer the question you need each producer's opportunity cost, not their output level alone.

A point on the production possibilities curve represents productive efficiency: the economy is using all of its resources fully with its current technology, so it cannot produce more of one good without producing less of the other. Any move along the curve has an opportunity cost.

The law of increasing opportunity cost says that as an economy produces more of one good, each extra unit costs more of the other good. It happens because resources are not equally suited to both goods, and it is why the production possibilities curve bows outward.

Because each country gets its import for less than it would cost to make at home. When countries specialize by lower opportunity cost and trade at a rate between their two costs, world output rises and each country gains, even if one is more productive at everything.