EKN 110 Economics 110 Exam Notes & Summaries

EKN 110 (Economics 110) is typically the entry-level economics course that builds the foundation for how markets work, how economies operate at the macro level, and how policy choices affect households, firms, and governments. These exam notes focus on clear theory, step-by-step problem solving, and the kinds of short-answer and long-form questions commonly set in South African university Economics courses. The goal is not only to summarise topics, but to connect them into a coherent “exam toolkit” you can apply under time pressure.

Because “EKN 110” is often taught across different institutions and sometimes with slight variation in emphasis, these notes are written in an exam-friendly way that matches the usual curriculum structure: micro foundations (supply/demand, elasticity, market structures), basic welfare and policy (taxes, subsidies, price controls, market failure), and macro foundations (national income, unemployment, inflation, interest rates, and growth). Examples and study approaches are tailored for South African settings, including typical exam styles and the kind of contexts students see in locally relevant discussions.

Section 1: Core Microeconomics—Demand, Supply, Elasticity, and Market Outcomes (EKN 110 Essentials)

Microeconomics answers the question: how do individual consumers and firms make decisions, and what do those decisions imply for market prices and quantities? In most EKN 110 exams, the strongest marks come from (1) drawing correct graphs, (2) explaining direction of change, and (3) using elasticity correctly.

Demand: Law of Demand, Shifters, and Movement vs Shift

A standard starting point is the law of demand: holding other factors constant, when price rises, quantity demanded falls. The reason is usually explained using either:

Marginal utility and diminishing marginal returns (each additional unit is worth less),
Income and substitution effects (particularly relevant for normal goods),
Opportunity cost (consumers substitute away from expensive alternatives).

Movement along the demand curve vs shift of the demand curve

Examiners often penalise students for confusing these concepts.

Movement along demand curve occurs when price changes (P → new Qd).
Shift of demand curve occurs when a non-price determinant changes (income, tastes, prices of related goods, expectations, number of buyers).

Key demand shifters (typical exam list)

Income (Y)
- Normal good: higher income → demand shifts right.
- Inferior good: higher income → demand shifts left.
Prices of related goods
- Substitutes: price of substitute rises → demand for this good increases (right shift).
- Complements: price of complement rises → demand decreases (left shift).
Tastes and preferences
Advertising trends or lifestyle changes shift demand.
Expectations
If consumers expect future price increases, they buy more now → right shift.
Number of buyers
More buyers → right shift.
Population demographics (in SA contexts: e.g., youth vs older cohorts affecting consumption patterns).

Example scenario (typical in exams)

Suppose the price of public transport fares increases. For a substitute like ridesharing:

If ridesharing is considered a substitute, then demand for ridesharing shifts right when transport fares rise.
But if the two are complements (e.g., ridesharing used as an “access service” to public transport), then demand may fall.
Your task is to state clearly whether the goods are substitutes or complements and then predict the direction.

Supply: Law of Supply, Shifters, and Producer Behaviour

The law of supply usually states that, holding other factors constant, when price rises, quantity supplied rises. Explanations:

At higher prices, firms cover costs and earn higher profits.
Firms allocate more labour and output to the market.

Supply curve: movement vs shift

Movement along supply: price changes → new quantity supplied.
Shift of supply: non-price factors change.

Key supply shifters (typical list)

Input prices (wages, raw materials, energy)
Technology (improved productivity shifts supply right)
Taxes/subsidies (tax on production shifts supply left; subsidy shifts right)
Number of sellers (more firms → supply increases)
Expectations (if future prices expected to rise, firms may supply less today → left shift)
Regulation and compliance costs (environmental standards, licensing)

Equilibrium: Market-Clearing Price and Quantity

The market equilibrium is where quantity demanded equals quantity supplied.

Graphically: intersection of demand and supply.
Economically: at equilibrium, there is no systematic shortage or surplus.

Changing equilibrium: prediction rules

A frequent exam question asks: “If X happens, what happens to equilibrium price and quantity?”

Procedure:

Identify whether the event is a demand shifter or supply shifter.
Draw initial curves.
Shift the relevant curve right/left.
Read off new equilibrium price and quantity.
Provide a short explanation using relative magnitude and direction.

Common pitfalls

Students sometimes shift both curves without justification.
Others incorrectly claim that both price and quantity must always increase. Correct predictions depend on which curve shifts more relative to the other.

Elasticity: The Most Exam-Tested Concept

Elasticity measures responsiveness of quantity to changes in some variable, typically price.

Price elasticity of demand (PED)

[
PED = \frac{%\ \Delta Q_d}{%\ \Delta P}
]
Key facts:

Usually negative for demand because higher price reduces quantity demanded.
In many exam contexts, elasticity is reported as an absolute value (positive number).
The magnitude matters:
- |PED| > 1: elastic (quantity responds strongly)
- |PED| = 1: unit elastic
- |PED| < 1: inelastic

Interpreting elasticity using total revenue (TR)

When price changes:

If demand is elastic, TR changes in the direction of price decrease → TR increases.
If demand is inelastic, TR changes in the direction of price increase → TR increases.

A classic exam question: “A firm increases price. Does its revenue increase or decrease?”
Answer depends on elasticity.

Factors that influence PED

Availability of substitutes
More substitutes → more elastic.
Necessity vs luxury
Necessities are often inelastic.
Time horizon
In the long run, consumers adjust more → demand becomes more elastic.
Share of income
Larger share → more responsive → more elastic.
Definition of the market
Broad categories are less elastic; narrow categories more elastic.

Cross Elasticity and Income Elasticity (Often Short Questions)

Cross elasticity of demand (XED)

[
XED = \frac{%\ \Delta Q_x}{%\ \Delta P_y}
]
Interpretation:

XED > 0 → substitutes.
XED < 0 → complements.
XED = 0 → unrelated goods.

Income elasticity of demand (YED)

[
YED = \frac{%\ \Delta Q}{%\ \Delta Y}
]
Interpretation:

YED > 0: normal good.
YED < 0: inferior good.
YED > 1: luxury (income rises faster than demand).
0 < YED < 1: necessity.

Market outcomes under price ceilings and floors (Policy impact)

Even in a foundational course, exams often test understanding of how interventions change outcomes.

Price ceiling (maximum price)

Binding ceiling is below equilibrium price.
Effects: shortage (Qd > Qs) and rationing.
May lead to black markets or non-price rationing (quality deterioration).

Price floor (minimum price)

Binding floor is above equilibrium price.
Effects: surplus (Qs > Qd).
Leads to potential government procurement or stockpiling.

Taxes and subsidies (basic incidence)

A tax on sellers or buyers creates a wedge between:

the price paid by buyers,
the price received by sellers.

Even if the tax is “on sellers,” some burden is shared depending on relative elasticities. The side with more inelastic demand/supply bears more burden.

Mini-case style examples (SA context framing, without assuming unique local data)

Rising bread prices
Bread often considered a necessity with fewer substitutes → more inelastic demand. A tax on production likely affects quantity less but price more.
Electricity price changes and household consumption
Electricity demand can be relatively inelastic in the short run due to limited immediate alternatives; in the long run, households adopt energy-saving and alternative sources → demand becomes more elastic.
Transport market and ride-share
If public transport fares rise, demand for ride-share might increase (substitution) but could also shift depending on complementary patterns (e.g., ride-share used to access trains).

Summary checklist for Section 1 (High-yield exam points)

When answering microeconomics questions, always include:

Whether it’s a shift or a movement
Correct direction of shift (right/left)
Correct prediction for equilibrium price and quantity
Elasticity interpretation using responsiveness
For taxes: mention incidence depends on relative elasticities

Section 2: Consumer Choice, Utility, Costs, Production, and Market Structures—From Curves to Conclusions

This section covers the “how” behind economic behaviour: consumers choosing bundles and firms choosing output. It also connects those choices to market structures (perfect competition, monopoly, and sometimes monopolistic competition/oligopoly at a basic level).

Consumer Choice: Utility, Budget Constraints, and Indifference Curves

Utility and preferences

Economics assumes consumers have preferences that are:

complete (they can compare any two bundles),
transitive (if A preferred to B and B to C, then A preferred to C).

Budget constraint

The budget line reflects available income:
[
P_x x + P_y y \leq I
]
where:

(P_x, P_y) are prices of goods x and y,
(I) is income.

Graphically:

downward sloping line,
intercepts show maximum possible spending on each good.

Indifference curves

Indifference curves show combinations of goods giving the same utility.

Typically convex to the origin (diminishing marginal rate of substitution).
Higher indifference curves represent higher utility.

Optimal choice: Tangency principle

The consumer maximises utility where:

the budget line is tangent to an indifference curve.
At tangency:
[
MRS_{x,y} = \frac{P_x}{P_y}
]
Meaning: the consumer’s willingness to trade equals market opportunity cost.

Income and substitution effects (intuition and typical exam explanation)

When price of one good changes, demand responds through:

Substitution effect: relative price changes → consumer substitutes away from the more expensive good.
Income effect: real purchasing power changes → consumption of normal/inferior goods changes accordingly.

For Giffen goods (rare and often not deeply covered in EKN 110), income effect dominates substitution effect.

Consumer Demand: From Indifference to Demand Curve (Conceptual Link)

Students sometimes get stuck on the bridge between choice theory and market demand. The exam-ready way to state it:

As price changes, the budget line pivots.
Tangency points trace out the demand curve for that good.
The consumer chooses higher utility points subject to budget.

You don’t always need to derive mathematically in EKN 110, but you must explain directionally and graphically.

Production and Costs: Firm Decision-Making

Production function (general idea)

A production function links inputs to output:
[
Q = f(L, K)
]
where:

(L) = labour input
(K) = capital input

Short-run vs long-run

Short run: at least one factor fixed (commonly capital).
Long run: all factors variable.

Total, average, and marginal products

Often tested:

Total Product (TP) increases with labour initially but may eventually decline if diminishing returns start.
Marginal Product (MP): extra output from extra labour.
Diminishing marginal returns: as more of a variable input is added to fixed input, MP eventually falls.

Cost concepts

Key quantities:

Total Cost (TC)
Average Cost (AC): (AC = \frac{TC}{Q})
Average Fixed Cost (AFC): (AFC = \frac{TFC}{Q})
Average Variable Cost (AVC): (AVC = \frac{TVC}{Q})
Marginal Cost (MC): extra cost of producing one more unit

Graph relationships often asked:

MC intersects AC and AVC at their minimum points.

Profit maximisation: where MR = MC (depending on market structure)

A recurring exam theme is:

Firms choose output to maximise profit, often where marginal revenue (MR) equals marginal cost (MC).
In perfect competition: price is constant and equals MR, so the firm produces where P = MC (subject to shut-down conditions).

Shut-down rule (basic version)

A firm shuts down in the short run if:

price is below average variable cost (P < AVC), because it cannot cover variable costs.

Market structures: what changes the firm’s revenue curve?

Perfect competition (foundational)

Assumptions:

many firms,
identical products,
firms are price takers,
free entry/exit.

Consequences:

firm demand is perfectly elastic,
MR = P.

In the long run:

economic profits go to zero (price equals average total cost for the efficient scale).

Monopoly (foundational)

Assumptions:

one seller,
barriers to entry,
downward-sloping demand,
MR < P (because selling more requires lowering price).

Consequences:

Monopoly sets output where MR = MC,
then reads price from the demand curve.
Typically higher price and lower quantity than perfect competition.

Welfare and deadweight loss (connects micro to policy and exam essays)

In monopoly:

Reduced output relative to competitive outcome creates deadweight loss.
In many exams, students must contrast:
- allocative efficiency (where marginal benefit equals marginal cost),
- and how market power prevents that.

Monopolistic competition and oligopoly (if included)

EKN 110 may introduce these at a conceptual level:

Monopolistic competition: many firms, differentiated products, some market power, downward-sloping demand.
Oligopoly: few firms, strategic interaction, barriers, interdependence.

If these are not in your syllabus in full detail, the safest exam approach is:

define briefly,
emphasise interdependence (for oligopoly),
note long-run entry effects (for monopolistic competition).

Worked example template: cost curves and profit

You may see a question like:

given information about costs at different quantities,
compute which quantity maximises profit.

A standard step-by-step method:

Compute TR = P × Q (if P known).
Compute Profit = TR − TC for each Q.
Identify maximum profit.
If asked conceptually, explain using marginal reasoning: “Increase Q until MR < MC.”

Even if you don’t compute exactly, examiners reward correct method.

Mini-case: “Firm in a changing cost environment” (example reasoning)

If input prices rise due to energy costs:

MC shifts upward (or supply shifts left in market terms).
Market equilibrium price rises and quantity falls.
Elasticity affects final incidence: consumers may reduce demand strongly if substitutes exist.

This links directly to Section 1 elasticity and taxes.

Summary checklist for Section 2

For high marks, ensure you can:

Define and draw budget constraint and indifference curves
State optimality condition (MRS = Px/Py)
Distinguish short-run vs long-run production and costs
Use cost curve logic: MC intersects AC and AVC at minima
Explain MR = MC and how market structure alters MR and P relationship
Describe welfare implications: deadweight loss and inefficiency

Section 3: Market Failure, Government Intervention, and Welfare Analysis—Taxes, Subsidies, Externalities, and Public Goods

Economics becomes policy-relevant once markets fail to deliver efficient outcomes. EKN 110 exams commonly ask: why markets may not work well, and what governments can do, including both benefits and unintended consequences.

Efficiency benchmarks: Pareto efficiency and social surplus

A useful exam foundation is to understand what “efficiency” means.

Pareto efficiency: no one can be made better off without making someone else worse off.
In many welfare discussions: efficiency corresponds to equating marginal social benefit (MSB) and marginal social cost (MSC).

In competitive markets without distortions:

private marginal benefit (PMB) equals private marginal cost (PMC), and market outcome can be efficient.

When externalities exist:

PMB ≠ MSB or PMC ≠ MSC, and efficiency fails.

Externalities: Negative and Positive

Negative externality (production/consumption spillovers)

Example: pollution from a factory affecting nearby residents.

Private marginal cost (PMC) is lower than marginal social cost (MSC) because firms ignore external harm.
Market produces too much relative to the socially optimal quantity.

Graph logic:

Demand may represent PMB or marginal benefit; supply represents PMC.
Social optimum occurs where MSB = MSC.
The gap leads to deadweight loss.

Positive externality

Example: vaccinations improving public health.

Private marginal benefit (PMB) is less than marginal social benefit (MSB).
Market produces too little relative to optimal.

Government responses to externalities

Pigouvian taxes (for negative externalities)

A tax equal to marginal external damage:

shifts firm’s marginal cost to MSC,
reduces output to socially optimal level.

Pigouvian subsidies (for positive externalities)

A subsidy equal to marginal external benefit:

shifts marginal benefit upward,
increases output/consumption toward efficient level.

Cap-and-trade (if discussed)

Cap sets a maximum pollution level; trade allows firms to exchange allowances.

Achieves quantity constraint but price of permits adjusts.
Efficiency depends on cap level and market functioning.

If your course does not cover cap-and-trade deeply, you can still mention it briefly as an alternative to Pigouvian taxes.

Taxes and subsidies revisited: incidence and distortion

Even when government aims to correct market failure, it changes incentives.

Tax incidence

Students should not assume tax burden falls entirely on sellers or buyers. The incidence depends on:

elasticity of supply and demand.

A good exam answer:

If demand is inelastic, consumers bear more burden.
If supply is inelastic, producers bear more burden.

Deadweight loss from taxation

A distortionary tax causes:

reduced quantity exchanged,
welfare loss beyond the tax revenue.

In externality cases, however, taxes can be efficiency-improving if they correct misallocation. So exam questions may ask you to compare:

tax as a distortion vs
tax as correction.

Public goods and the free-rider problem

Public good definition

A public good has:

non-rivalry: one person’s consumption doesn’t reduce availability to others,
non-excludability: difficult to prevent non-payers from benefiting.

Example: street lighting, national defence, some public health initiatives.

Free rider problem

If people can benefit without paying, private markets may underprovide public goods.

Graphically:

private demand reflects marginal private benefit,
social demand sums marginal benefits across individuals.

Hence the market equilibrium quantity is typically less than the socially efficient quantity.

Government solutions

compulsory taxation and public provision,
or subsidies and regulated provision.

Information failures: adverse selection and moral hazard (often included)

EKN 110 may include these topics as “basic” market failure due to asymmetric information.

Adverse selection

Before a transaction, one party has more information.
Example: insurance markets where higher-risk individuals are more likely to buy insurance.
Result: average risk rises → premiums rise → lower-risk individuals drop out → can spiral.

Moral hazard

After a transaction, behaviour changes because the party is protected.
Example: insured drivers may drive less carefully.

Government policy responses may include:

screening tests,
contracts with incentives,
monitoring,
co-payments/deductibles.

Even if exam questions are conceptual, you should define terms clearly and relate to “why markets fail.”

Price controls and welfare effects (worked qualitative reasoning)

If governments impose ceilings/floors:

allocate scarce resources through non-price methods,
can reduce welfare relative to free market outcome.

A high-quality exam response typically mentions:

quantity mismatch,
rationing mechanism,
effect on quality/innovation,
and who gains/loses (consumer surplus vs producer surplus).

Cost-benefit thinking and equity vs efficiency

Some exam questions go beyond efficiency and ask about fairness. You can use the language:

equity: who pays and who benefits,
efficiency: how well resources are allocated.

A government intervention might improve equity but reduce efficiency, or vice versa. For example:

redistribution via taxation can create efficiency loss (deadweight loss),
but can improve outcomes for low-income households.

Mini-case style reasoning (policy in South African contexts—without needing precise local numeric datasets)

Education and vaccination policies
Education often has positive externalities (better health, productivity, social cohesion). Vaccination has positive spillovers (herd immunity).
Government can justify subsidies or funding because private demand underestimates social benefits.
Pollution regulation
Industries may pollute due to private costs being lower than social costs. Regulations, taxes, or tradable permits can correct this wedge.
Rent control or minimum wage floors
Price floors/ceilings create shortages or surpluses if binding. But policy may be justified on equity grounds, especially with unemployment or poverty.

Summary checklist for Section 3

Ensure you can:

Define externalities and explain over/underproduction
Use MSB/MSC logic for welfare outcomes
Explain Pigouvian taxes/subsidies and how they change incentives
Discuss public goods and why markets underprovide
Define adverse selection vs moral hazard
Explain price controls’ welfare consequences
Balance equity vs efficiency in policy answers

Section 4: Macroeconomics Foundations—National Income, Inflation, Unemployment, Money, and Growth (EKN 110 Macro Toolkit)

Macroeconomics studies the performance of an entire economy. EKN 110 exams often test:

national income accounting,
unemployment and labour market concepts,
inflation measurement and causes,
money and interest rates (basic),
economic growth and the determinants of growth,
and possibly aggregate demand/supply (basic model or at least components).

National income accounting: GDP, GNP (conceptual) and the identity approach

GDP definition (exam-friendly)

GDP measures the market value of final goods and services produced within a country over a period (usually a year).

Three ways to measure GDP

A classic exam expects you to know:

Expenditure approach
Income approach
Production approach

The expenditure approach is most common in entry-level exams:
[
GDP = C + I + G + (X – M)
]
Where:

(C) = consumption,
(I) = investment,
(G) = government spending,
(X) = exports,
(M) = imports.

Final goods vs intermediate goods

If you include intermediate goods, you double-count value. Only final goods count.

A typical exam trap:

“Buying flour” vs “buying bread.” Bread is final; flour is intermediate if used to make bread.

Real vs nominal GDP and inflation adjustment

Nominal GDP

Uses current prices.

Real GDP

Adjusts for inflation using a base year price index.

[
Real\ GDP = \frac{Nominal\ GDP}{Price\ Index/100}
]

GDP deflator

Often defined as a price index measure for all domestically produced goods:

helps convert nominal to real and allows inflation rate calculation.

Calculating GDP growth and inflation (conceptual plus step arithmetic)

Common tasks:

given values, compute growth rates,
compute inflation rates from price index data.

A basic method:
[
Inflation\ Rate = \frac{Index_{t} – Index_{t-1}}{Index_{t-1}} \times 100%
]

If asked to compute, show formula clearly.

Business cycle basics: output fluctuations and policy response

Macroeconomy experiences cycles:

expansions,
peaks,
recessions,
troughs.

In recessions:

unemployment rises,
demand falls,
government may consider expansionary fiscal policy (increase G, cut taxes) and/or monetary policy (reduce interest rates, increase money supply), depending on the model coverage.

Unemployment: types and measurement

Labour force and unemployment rate (core identity)

Unemployment rate:
[
u = \frac{Unemployed}{Labour\ Force} \times 100
]

Types of unemployment

Frictional: between jobs, search time.
Structural: mismatch between skills and job requirements.
Cyclical: due to insufficient aggregate demand.

Entry-level exams often ask:

which unemployment is higher during recession (cyclical),
which persists even in good times (structural).

Labour market implications

High unemployment can reduce output (recession costs) and harm long-run skills and employability (hysteresis—sometimes advanced but can be referenced conceptually if your course touches it).

Inflation: causes, effects, and measurement

Types/causes of inflation (basic frameworks)

Common exam categories:

Demand-pull inflation: aggregate demand rises faster than productive capacity.
Cost-push inflation: input costs rise (wages, oil, imported inputs), shifting costs and prices upward.
Monetary inflation: excessive money growth relative to output.

Some curricula also mention inflation expectations:

if households and firms expect inflation, they adjust wages/prices, making inflation persistent.

Measuring inflation: CPI vs other indices

In South Africa, exams may reference CPI as widely used consumer inflation measure. The exam may not require specific CPI weighting detail, but you must understand:

CPI measures price changes of a basket of consumer goods and services.
“Basket” composition matters: rising food and fuel costs can heavily influence CPI.

Effects of inflation

reduces purchasing power,
creates “menu costs” and uncertainty,
may redistribute income between debtors and creditors (depending on nominal interest rates),
can affect competitiveness via real exchange rate changes.

Money, interest rates, and basic monetary policy

EKN 110 macro typically introduces:

money demand and supply,
central bank operations (conceptual),
interest rate as the “price of money.”

Monetary policy tools (conceptual)

open market operations (buy/sell government securities),
reserve requirements,
policy interest rate adjustments.

Expansionary monetary policy usually:

lowers interest rates,
increases investment and consumption (depending on elasticity of response),
increases aggregate demand in the short run.

Contractionary monetary policy:

increases interest rates,
reduces spending,
aims to reduce inflation.

Aggregate demand and aggregate supply (if included in your syllabus)

If your course covers the AD-AS model:

AD slopes downward: price level ↑ → real money balances ↓ → consumption/investment ↓ → output ↓.
AS can be short-run upward sloping due to sticky wages/prices.
Long-run AS vertical at potential output (in many textbook versions).

Even if you don’t do full graph interpretation, you should be able to explain:

how inflation and unemployment can be affected differently in short run vs long run.

Economic growth: sources and measurement

Growth accounting (conceptual)

Economic growth can come from:

labour (more workers),
capital accumulation (more machinery/buildings),
technology/productivity improvements.

In simple exam language:

productivity is central: output per worker.

Determinants of growth (typical exam list)

human capital (education, skills),
infrastructure,
institutions and governance,
investment climate,
innovation and R&D,
trade openness and learning-by-exporting,
macroeconomic stability.

Mini-case reasoning: unemployment + inflation + growth tensions

An exam question may ask you to interpret a scenario:

inflation is rising,
unemployment is high,
GDP growth is slowing.

A good response discusses:

possible causes: supply shocks (cost-push), demand changes, monetary/financial tightening,
policy trade-offs: tightening may reduce inflation but increase unemployment in short run,
longer-term reforms: productivity, skills, labour market matching.

Summary checklist for Section 4

Be ready to:

Use (GDP = C + I + G + (X – M))
Explain real vs nominal GDP and compute simple growth/inflation rates if asked
Define unemployment rate and distinguish frictional/structural/cyclical
Explain demand-pull vs cost-push and major effects of inflation
Explain monetary policy conceptually and its macro impact
Explain growth determinants and why productivity matters

Section 5: Exam Writing Skills—How to Answer EKN 110 Questions Perfectly (Graphs, Essays, Calculations, and South African Assessment Style)

Many students know the theory but lose marks on exam technique. This section is a high-yield training module: it focuses on answer structure, graph standards, common marking rubrics, and calculation steps that examiners reward in Economics courses at South African universities, colleges, and TVETs.

How to structure short questions (5–10 marks)

For short questions, speed matters but clarity matters more.

Use a template:

Definition (1 sentence)
Key mechanism (2–3 sentences)
Result/direction (1–2 sentences)
Tiny justification (why it follows)

Example: “Explain price elasticity of demand.”

Definition with formula or meaning
Mention elastic vs inelastic categories
Mention determinants (substitutes, time horizon)
Add one implication (total revenue or policy incidence)

How to structure long essays (20–30 marks)

A common rubric for Economics essays rewards:

correct theory,
correct graphs (if relevant),
coherent chain of logic,
and applied conclusion.

A strong essay structure:

Introduction: define core terms and identify the issue
Body paragraphs:
- Paragraph 1: describe market outcome under assumptions
- Paragraph 2: identify market failure or policy intervention
- Paragraph 3: show welfare impact (surplus/externalities/deadweight loss)
- Paragraph 4: discuss policy instruments + limitations
Conclusion: summarise “what happens” and “why” and any trade-offs

Example essay prompt style

“Using demand and supply analysis, explain the effects of a tax on a product. Discuss incidence and welfare effects.”

An exam-ready response:

state tax wedge,
show incidence depends on elasticities,
include deadweight loss and possible efficiency implications if correcting externalities.

Graph technique: what marks are usually given for

Even when the question is theoretical, graphs can earn free marks.

Graph checklist

Label axes with quantity (Q) on x-axis and price/cost (P) on y-axis.
Clearly indicate direction of shifts with arrows.
Use correct curve shapes (downward demand, upward supply).
Indicate equilibrium points clearly.
Provide labels for elasticities or surpluses (cs, ps) when asked.

Common graph errors

forgetting to label axes,
shifting the wrong curve,
drawing the new equilibrium but failing to state the direction of change,
confusing AC/MC intersections and minimums.

Calculation technique: show steps, not only answers

Exams in Economics often involve arithmetic. The best method:

Write the formula.
Substitute correctly with units/percent signs.
Show intermediate steps.
State final answer clearly (with sign and %).

Example calculation template

“Inflation rate given CPI values.”

Write inflation formula.
Substitute (CPI_t) and (CPI_{t-1}).
Compute and present %.

Linking micro and macro questions (how to score integrative marks)

Some papers include questions that connect both levels. Examples:

taxes affect demand/supply and thus output,
macro growth and unemployment influence household income and consumption,
inflation affects real interest rates and investment.

The trick is to make the link explicit:

“Changes in aggregate demand influence output and employment; output changes affect income, which shifts consumption (micro underpinning of C in GDP identity).”

Typical question types and model-style answers (without pretending exact past papers)

Type A: Elasticity and policy incidence

Prompt: “A government imposes a tax on fuel. Explain who bears the burden.”

Model answer structure:

define tax incidence,
mention relative elasticities,
state: more inelastic side bears more burden,
connect to real-world: fuel has fewer substitutes in short run → likely higher consumer burden short run.

Type B: Externalities and corrective taxes

Prompt: “Explain how a Pigouvian tax can correct a negative externality.”

Model answer structure:

define externality,
show divergence between private and social costs,
tax internalises externality,
show reduction in output and welfare improvement compared to unregulated outcome (reduced deadweight loss).

Type C: National income accounting

Prompt: “Given C, I, G, X, M, compute GDP and interpret changes.”

Model answer structure:

compute GDP using identity,
interpret: if G rises and other components constant → GDP rises by that amount, but in real world can also affect M and C through multiplier/interest rate effects (depending on syllabus depth).

Counter-arguments and limitations (the mark booster)

Many essays require a balanced view. Add 2–3 limitations:

externality taxes may be hard to measure,
behavioural responses may be different than assumed,
taxes can be regressive without compensation,
public goods provision can face inefficiency/corruption problems,
macro policy may conflict with inflation and unemployment goals in short run.

Examiners often award marks for acknowledging that:

“the theoretical solution may face real implementation constraints.”

Time management strategy for an exam

A practical plan:

Scan the paper first (2–3 minutes).
Identify high-score questions you’re confident in.
Attempt those first to build momentum.
For graph questions, draw the axis and initial curves immediately.
For calculation questions, write the formula early.
Keep an eye on word count for essays: structure matters more than writing too much.

Rapid revision summary: the “EKN 110 memory map”

To revise effectively, remember the flow:

Demand & supply → equilibrium.
Elasticity → responsiveness and incidence.
Consumer choice & costs → micro foundations of behaviour.
Market failure → externalities/public goods/information failures.
Government intervention → taxes/subsidies/controls + welfare impacts.
National income → GDP via expenditure identity.
Unemployment & inflation → key macro indicators.
Monetary/fiscal policy → influence on output and prices.
Growth → productivity and long-run determinants.

Institution-Focused Study Cluster Note (Consistency with “University of Pretoria (UP) BCom Economics Study Material” Use)

The following cluster is written to align with how South African economics study material is often organised within the University of Pretoria (UP) BCom Economics Study Material context. Even if your exam paper uses slightly different wording, the underlying concepts remain the same, and these clusters help you practise targeted recall.

UP-Cluster: EKN 110 Economics 110—Institution-Style Revision Plan for Micro + Macro

What to practise for UP-style Economics exams (typical focus)

Micro graphs: equilibrium shifts, taxes, subsidies, price ceilings/floors, and monopoly vs competition comparisons.
Elasticity questions: calculate/interpret elasticity and discuss implications for firms and governments.
Welfare analysis: externalities, deadweight loss, and public goods free-riding logic.
Macro computations: GDP identity and converting nominal to real conceptually.
Macro interpretation: explain unemployment/inflation trade-offs and policy directions.

“One-page” practice set (make your own)

Draw demand and supply shift with equilibrium change.
Draw tax wedge and label buyer price vs seller price.
Draw negative externality: PMC, MSC, deadweight loss triangle.
Draw positive externality: PMB, MSB, underconsumption triangle.
Write GDP identity and explain C/I/G/(X−M) with one example each.
Define unemployment rate and unemployment types.
Define CPI and explain demand-pull vs cost-push inflation in 3 lines each.

How to convert practice into marks

In every answer: use economic language (“shifts,” “incidence,” “welfare,” “marginal”).
In every graph: label axes, equilibrium, and identify whether curve is shifting or moving.
In every calculation: write formula first.

Final High-Yield Exam Summary (All Sections)

Section 1 (Micro core): demand/supply, equilibrium, elasticity, and how policies create shortages/surpluses and incidence.
Section 2 (Behaviour & firms): consumer choice (utility + budget constraint), firm costs and profit maximisation, and how market structure changes MR and outcomes.
Section 3 (Market failure & welfare): externalities, public goods, asymmetric information, and government instruments with welfare reasoning.
Section 4 (Macro core): GDP accounting, real vs nominal, unemployment types, inflation causes/effects, and basic monetary-policy logic.
Section 5 (Exam technique): how to structure answers, how to draw graphs correctly, how to calculate, and how to add counter-arguments.

If you can apply these consistently—correctly, clearly, and with proper graph and formula usage—you’ll be positioned to score highly across a typical EKN 110 Economics 110 exam paper in a South African higher-education context.