EKN0A11—Principles of Economics & Business—introduces the foundational logic behind how economies allocate scarce resources and how firms operate within those constraints. The module typically blends core economic concepts (demand, supply, elasticity, market structures, and market outcomes) with business fundamentals (costs, pricing intuition, basic finance thinking, and how decision-makers respond to incentives). These exam notes focus on approaches that align with South African university expectations, particularly the style commonly used in University of Johannesburg (UJ) economics module guides, where clarity of definitions, step-by-step reasoning, and applied examples are crucial.
1) Microeconomic Foundations: Scarcity, Choice, Demand, and Supply
Microeconomics studies how individual households and firms make decisions and how these decisions interact in markets. The “principles” nature of EKN0A11 means you must be fluent in basic models and able to apply them to realistic situations—especially South African contexts such as fuel prices, food markets, housing affordability, and wage dynamics.
1.1 Scarcity, Opportunity Cost, and Incentives
Scarcity means resources are limited relative to wants. This does not only refer to physical shortage; it also includes time, skills, budget constraints, and managerial capacity.
- Opportunity cost is the value of the next best alternative forgone.
- Incentives are changes in costs/benefits that influence behaviour.
Exam framing: Many exam questions test whether you can distinguish accounting cost from economic cost (opportunity cost). In business decision-making, ignoring opportunity cost can lead to misleading “profit” calculations.
Example: Opportunity cost in a small business
A student starts a tutoring service from home.
- Accounting costs: stationery R500, data costs R600, transport R400 (total R1 500).
- If the student could have worked part-time earning R2 000 per month, that R2 000 is an economic cost (opportunity cost).
So economic profit depends not just on explicit expenses but on the best alternative.
Incentives and behavioural responses
If government increases a tax on sugary drinks:
- Retailers may adjust prices.
- Consumers may switch to substitutes.
- Producers may reformulate products or reduce marketing.
The direction of response depends on elasticities (covered later). But the core principle is: incentives change choices.
1.2 Demand: The Logic of Willingness and Ability
A demand curve shows the relationship between the price of a good and the quantity demanded, holding other factors constant.
The law of demand
Typically, as price rises, quantity demanded falls because:
- Consumers face higher costs (substitution effect).
- Real purchasing power declines (income effect, especially for normal goods).
- Some demand is driven by budget limits.
Determinants of demand (non-price factors)
In exams, differentiating changes in demand vs changes in quantity demanded is a common marker for good comprehension.
- Income (especially for normal goods)
- Tastes and preferences (advertising, health trends)
- Prices of substitutes and complements
- Expectations (future price/income expectations)
- Number of buyers
- Seasonal factors
Change vs shift
- Change in quantity demanded: movement along a demand curve caused by a price change.
- Change in demand: shift of the demand curve caused by changes in non-price determinants.
1.3 Supply: Costs, Technology, and Producer Behaviour
A supply curve shows the relationship between price and quantity supplied.
Law of supply
Typically, as price rises, quantity supplied rises because producers can cover costs and gain profit.
Determinants of supply
- Input prices (wages, raw materials)
- Technology and productivity
- Taxes/subsidies
- Number of sellers
- Expectations of future prices
- Weather and natural constraints (important in agriculture)
1.4 Market Equilibrium and Price Signals
Equilibrium occurs where quantity demanded equals quantity supplied.
At equilibrium:
- There is no incentive for buyers and sellers to change quantity (within the model assumptions).
- Price acts as a signal coordinating plans.
Excess demand and excess supply
- If price is below equilibrium: excess demand creates shortages → upward price pressure.
- If price is above equilibrium: excess supply creates surplus → downward price pressure.
Policy relevance: price controls
In South Africa, exam-style questions sometimes reference rent controls or intervention in essential goods. Price ceilings and floors often produce shortages/surpluses unless set at equilibrium.
1.5 Worked Demand–Supply Scenarios (SA-style)
Scenario A: Fuel price increase and transport costs
Suppose the price of fuel rises (an input for transportation and delivery).
- This increases costs, so supply of many services shifts left (reduced supply at each price).
- Prices of transport-related services may rise.
- Demand for transport may fall depending on elasticity.
How to answer in an exam:
- Identify whether the shock is to demand or supply (or both).
- Draw the correct direction of shift.
- State new equilibrium price and quantity direction qualitatively.
Scenario B: Health trend increases demand for low-sugar products
A health campaign increases demand for low-sugar beverages.
- Demand shifts right → equilibrium price rises (in most cases) and quantity rises.
A key skill is making correct qualitative conclusions without needing exact numbers unless given.
2) Elasticity, Market Efficiency, and Policy Trade-offs
Elasticity measures how responsive quantity is to changes in price or income. Many policy questions reduce to elasticity: tax burdens, incidence, and the effect of price regulation.
2.1 Understanding Elasticity (Core Definitions)
Elasticity of demand:
- Price elasticity of demand (PED) measures % change in quantity demanded due to a 1% change in price.
- Usually, PED is negative (because demand slopes downward), but exam questions often ask for absolute values.
Income elasticity of demand (YED):
- Positive for normal goods.
- Negative for inferior goods.
Cross-price elasticity:
- Positive for substitutes.
- Negative for complements.
Interpreting elasticity values
- |PED| > 1: elastic demand (quantity responds strongly)
- |PED| < 1: inelastic demand (quantity responds weakly)
- |PED| = 1: unit elastic (revenue stays constant under small price changes)
2.2 Using Elasticity to Predict Revenue and Expenditure
A common exam application: determine how total revenue changes when price changes.
Total revenue (TR) logic:
- TR = P × Q
- If demand is elastic: price ↑ → quantity ↓ more than proportionally → TR falls.
- If demand is inelastic: price ↑ → quantity ↓ less than proportionally → TR rises.
Example: bottled water vs luxury beverages
Bottled water often has more inelastic demand (few immediate substitutes for some consumers).
Luxury beverages may have more elastic demand (consumers can delay purchases or switch).
2.3 Elasticity and Tax Incidence (Who really pays?)
In many modules, tax incidence is a key “principles” topic: even if tax is levied on one side (buyers or sellers), the economic burden depends on elasticity.
- If demand is more inelastic than supply: buyers bear more of the tax.
- If supply is more inelastic than demand: sellers bear more.
Why? Because the side that is less able to adjust quantity at the new price absorbs more of the burden.
Numerically consistent mini-example
Imagine a tax increases effective price to consumers and reduces received price to firms. Without fully computing a model with specific curves, the qualitative incidence rule suffices in most EKN0A11 exam questions.
But if a question provides elasticities explicitly, you must apply the rule directly.
2.4 Elasticity and Policy Effectiveness
Policies—like subsidies, price controls, and taxes—can be evaluated through elasticity:
- Subsidy to producers/consumers:
- If demand is elastic, consumer subsidies may increase quantity significantly.
- Taxes:
- Elastic demand leads to greater reduction in quantity (more deadweight loss).
- Price floors/ceilings:
- Inelastic supply or demand affects magnitude of shortages/surpluses.
2.5 Deadweight Loss and Efficiency
Deadweight loss (DWL) occurs when the market outcome is inefficient due to intervention creating a wedge between price paid and price received.
To describe this:
- Under perfect competition without distortions, equilibrium maximizes total surplus (under standard assumptions).
- Taxes and price controls reduce trades beneficial to both parties.
Consumer surplus and producer surplus
- Consumer surplus: willingness to pay above actual price.
- Producer surplus: actual price received above marginal cost.
Efficiency insight: Policies often shrink the “surplus pie” by reducing mutually beneficial transactions.
2.6 Market Structures and Competitive Outcomes (Intro level)
EKN0A11 may cover basic market structures:
- Perfect competition (many firms, homogeneous product, price takers)
- Monopoly (single seller, pricing power)
- Monopolistic competition (differentiated products)
- Oligopoly (few firms, strategic interaction)
Principle-level comparison:
- Market power in monopolies reduces output and increases price relative to competitive outcome (in simplified models).
- Innovation and product differentiation can benefit consumers even under imperfect competition, but allocative inefficiency remains a typical trade-off.
2.7 Applying Elasticity and Structure to Business Decisions
Businesses also use elasticity:
- Set prices where demand is responsive but profit-maximizing.
- Adjust product mix when substitutes become available.
- Forecast how campaigns change demand.
Example: Pricing a student transportation package in Johannesburg
A transport operator offers a discounted monthly package.
- If students’ demand for transport is inelastic in the short run (they must travel), the operator can raise the package price slightly without large volume loss.
- If demand is elastic (alternative routes/time flexibility), a price increase reduces uptake significantly.
A strong exam answer links elasticity to business pricing strategy and consumer welfare.
3) Costs, Production, Pricing, and Firm Decision-Making
While microeconomics explains markets, business economics focuses on how firms operate. This section builds the decision logic of costs, production, and pricing—core content likely tested in EKN0A11.
3.1 Production and the Meaning of Production Functions
A production function links inputs to outputs.
A typical exam-friendly representation:
- Output depends on labour (L), capital (K), and technology (T).
- As technology improves, output at given inputs rises.
Diminishing marginal returns
In many introductory models:
- Holding capital constant, adding extra labour eventually yields smaller extra output from each added worker.
- This affects marginal cost and the cost curve shape.
3.2 Cost Concepts: Accounting vs Economic
Accounting cost includes explicit expenses: wages paid, rent, materials.
Economic cost includes:
- Explicit costs
- Implicit costs: opportunity cost of owner’s time, use of own resources
Economic profit vs accounting profit
- Accounting profit = revenue − explicit costs
- Economic profit = revenue − (explicit + implicit costs)
A firm may show positive accounting profit but negative economic profit if opportunity cost is high.
3.3 Fixed, Variable, and Total Costs
- Fixed costs (FC): do not change with output in the short run (rent, salaried staff).
- Variable costs (VC): change with output (materials, hourly labour).
- Total cost (TC) = FC + VC
Average and marginal costs
- Average cost (AC) = TC / Q
- Average fixed cost (AFC) = FC / Q
- Average variable cost (AVC) = VC / Q
- Marginal cost (MC) = change in TC from producing one more unit
Exam priority: Understand how MC relates to AC:
- When MC is below AC, AC falls.
- When MC is above AC, AC rises.
- MC crosses AC at AC’s minimum (in many textbook curves).
3.4 Break-even Analysis and Decision Rules
Break-even is where revenue equals total cost.
- If TR = TC → profit is zero (accounting profit).
- In economic terms, break-even may still involve implicit costs.
Short-run shutdown logic (simple version)
If price is below average variable cost, the firm may shut down in the short run because it cannot cover variable costs. Fixed costs remain but avoiding variable costs can reduce losses.
Important: Exams often ask you to choose shutdown vs continue based on comparisons to AVC.
3.5 Pricing Approaches: Cost-Based vs Market-Based
Firms rarely price in isolation; they consider costs and demand.
(A) Mark-up pricing (common in business)
- Price = cost × (1 + mark-up rate)
Strength:
- Simple and practical
Weakness:
- Ignores demand elasticity and competitive responses.
(B) Profit-maximization under competition (conceptual)
In perfect competition:
- Firms are price takers.
- They choose output where price equals marginal cost (P = MC) under standard assumptions.
In monopoly:
- Firm chooses output where marginal revenue equals marginal cost (MR = MC) and sets price from demand curve.
EKN0A11 may not require advanced MR derivations, but understanding the intuition helps:
- Monopoly prices are above marginal cost and output is lower than competitive.
3.6 Example: Costing a Production Decision for a South African Retailer
Consider a small retailer producing branded student notebooks.
Assume per month:
- Fixed costs: R20 000 (rent, equipment lease, supervisor salary)
- Variable cost per notebook: R10 (paper, printing ink, packaging labour)
- Output: Q notebooks
- Total cost: TC = 20 000 + 10Q
- If the notebook sells for R25 each, revenue TR = 25Q
Break-even occurs where:
- 25Q = 20 000 + 10Q
- 15Q = 20 000
- Q = 20 000 / 15 = 1 333.33 → approximately 1 334 notebooks
Interpretation in an exam: At Q ≈ 1 334, the firm covers costs. If it sells more than that, it likely generates positive accounting profit (assuming no additional fixed cost changes).
3.7 Production Efficiency and Business Strategy
Costs are not purely “accounting”; they guide strategy:
- Outsourcing vs in-house production
- Bulk purchasing vs just-in-time ordering
- Workforce planning to avoid underutilized capacity
- Process improvements reducing variable inputs per unit
Example: A TVET graduate starting a micro-enterprise
A graduate makes handcrafted gift items.
- If demand is highly seasonal (e.g., December), fixed costs should be minimized because revenue volatility is high.
- Variable costs must be controlled to preserve margin during slow months.
This is how micro cost principles connect to entrepreneurial realities.
4) Business in the Macroeconomic Context: GDP, Inflation, Unemployment, and Growth (Plus Basic Policy)
Even though EKN0A11 is partly micro-focused, business decisions depend on macroeconomic conditions. In a South African context, questions often connect inflation, interest rates, exchange rates, and unemployment to firm outcomes.
4.1 Measuring Economic Activity: GDP and Growth
GDP (Gross Domestic Product) measures total value of goods and services produced in an economy over a period.
Important distinctions:
- Real GDP adjusts for inflation (so growth reflects production changes, not price changes).
- Nominal GDP uses current prices (mixes price and quantity effects).
GDP and living standards (principle-level caution)
Economic growth does not automatically guarantee improved welfare if:
- income distribution worsens
- employment quality declines
- environmental damage increases
But GDP is still a primary indicator used in policy evaluation.
4.2 Inflation: Causes, Effects, and Business Implications
Inflation is a sustained rise in the general price level.
Common causes in introductory economics:
- Demand-pull inflation: aggregate demand exceeds supply capacity.
- Cost-push inflation: input costs rise.
- Inflation expectations: wages/prices adjust based on expected inflation.
Business effects
- Higher costs (materials, labour pressure)
- Uncertainty in budgeting
- Interest rate responses by central banks
- Changes in consumer demand (real income falls)
Example relevant to SA: If fuel prices rise, transport and production costs rise broadly, feeding into food and services prices.
4.3 Unemployment and Labour Markets
Unemployment reflects labour market matching issues, skill mismatches, wage-setting institutions, and economic cycles.
In exam terms, you may be asked to:
- distinguish structural vs cyclical unemployment
- interpret labour market statistics qualitatively
Structural unemployment
Occurs when labour skills do not match job requirements.
- Linked to education, training, and industrial policy.
South Africa’s TVET and higher education sector often plays a major role in addressing skill alignment.
4.4 Interest Rates and Investment Decisions
Interest rates affect:
- cost of borrowing for firms
- discount rates in investment appraisal
- consumer borrowing capacity
A higher interest rate environment typically:
- reduces investment and expansion projects
- increases pressure to manage working capital efficiently
4.5 Exchange Rates and Import/Export Businesses
In an open economy, exchange rate movements affect:
- import prices (and thus cost of inputs)
- export competitiveness (foreign demand)
If the local currency depreciates:
- imports become more expensive, increasing costs
- exports may become more competitive, raising demand (if foreign demand exists)
But firms also face hedging decisions, contractual price risks, and supply chain effects.
4.6 Government Policy: Fiscal and Monetary Tools
Fiscal policy (government spending and taxation)
- Stimulative fiscal policy may raise aggregate demand (in the short run).
- But it can increase deficits and debt if not controlled.
Monetary policy (central bank)
- Central bank influences inflation and growth through interest rates and liquidity management.
- Tight monetary policy reduces inflation but can slow growth and job creation.
Business connection: Firms anticipate policy directions when planning costs, inventory, hiring, and pricing.
4.7 A Coherent Case Narrative: Inflation and Firm Pricing Strategy
Consider a firm selling household cleaning products in Johannesburg:
- Inputs: imported chemicals and packaging (sensitive to exchange rates)
- Labour: wage agreements influenced by inflation expectations
- Demand: consumers trade down to cheaper brands when inflation reduces real incomes
In response, the firm may:
- Reduce production waste and optimize labour scheduling (lower unit costs).
- Adjust product mix (lower-cost variants).
- Use smaller pack sizes to maintain affordability (a common business tactic).
- Negotiate supplier contracts or switch to local suppliers to reduce currency risk.
In exam answers, such reasoning shows you can integrate micro (costs, demand) and macro (inflation, exchange rates) principles.
5) Applied Economics & Business Exam Skills: Problem Solving, Graphs, and Real-World Reasoning for EKN0A11
This final section is about how to perform well in exams: modelling correctly, interpreting diagrams, and answering in a way that earns marks. It also provides institution-relevant context for South African students: how to structure responses, what graders typically look for, and how to handle multi-part questions.
5.1 Graph Literacy: Demand–Supply and Cost Curves
A frequent EKN0A11 requirement is diagram interpretation and correct directional conclusions.
Demand–Supply diagram checklist
When a question changes a determinant:
- Decide if it is demand or supply.
- Determine direction of shift:
- Demand increases → shift right
- Demand decreases → shift left
- Supply increases (lower costs/technology improvement) → shift right
- Supply decreases (higher costs/weather) → shift left
- Identify new equilibrium:
- Price and quantity change direction
Cost curve reasoning checklist
When asked about cost relationships:
- FC constant, so AFC falls as Q increases.
- MC intersects AC and AVC at their minima (under typical curve shapes).
- If MC < AC, AC decreases (and vice versa).
Marking point: Many students draw the right curve but fail to state the economic interpretation. You need to explicitly translate diagram movements into business meaning.
5.2 Step-by-Step Answer Templates for Typical Exam Questions
Template A: “Explain the effect of X on Y using supply and demand”
- State the starting position (equilibrium).
- Identify whether X affects demand or supply (and justify briefly).
- Show shift direction.
- Conclude effect on equilibrium price and quantity.
- Mention possible second-round effects if relevant (e.g., elasticity, policy, substitutions).
Template B: “Calculate break-even output”
- Write revenue: TR = P × Q.
- Write total cost: TC = FC + VC per unit × Q.
- Set TR = TC.
- Solve for Q.
- Interpret results (how many units to cover costs).
Template C: “Tax incidence using elasticity”
- Identify whether demand or supply is more elastic.
- Use incidence rule:
- More elastic side bears less burden.
- Conclude who pays more and how quantity changes.
5.3 Case-Based Reasoning: Firms, Consumers, and Markets
In many economics-and-business modules, questions use short scenarios. You must identify the economic mechanism.
Case 1: Subsidy on public transport fares
Suppose government subsidizes bus fares:
- Consumers pay lower price → demand increases.
- If supply can respond (enough buses/drivers), equilibrium moves toward higher quantity.
- If supply is constrained, price can rise less/more depending on supply elasticity.
You should discuss:
- effect on quantity
- potential budget cost to government
- whether subsidy leads to improved welfare or inefficient allocation
Case 2: Price increases due to a commodity shock (food staples)
If staple food production declines due to drought:
- Supply shifts left → equilibrium price rises, quantity falls.
Business response:
- retailers adjust promotions
- consumers reduce consumption or switch to substitutes
Policy response:
- emergency food support
- targeted subsidies (but consider deadweight loss)
Your answer should mention:
- supply-side shock
- welfare changes (consumer surplus falls, producer surplus might rise)
- possible policy trade-offs
5.4 Multi-Part Questions: Avoiding Common Mistakes
Mistake 1: Confusing “change in demand” with “change in quantity demanded”
Always specify: “At a given demand, a price change moves along the curve.”
Mistake 2: Mixing up elasticity meaning
Elasticity is responsiveness, not simply “how much quantity changed.” You must convert to the logic of proportional change.
Mistake 3: Forgetting opportunity cost
If a question asks about decision-making, include opportunity cost explicitly.
Mistake 4: Graph without explanation
Diagrams are not substitutes for written reasoning. You must state the economic interpretation in words.
5.5 South African Context Focus: How to Apply Principles in Answers
EKN0A11 is taken by students who operate in a South African environment where:
- unemployment and skill mismatch are real constraints
- inflation affects affordability of goods and services
- policy changes can influence market outcomes (subsidies, taxes, interest rates)
To score well, include brief SA-relevant examples without getting overly specific about unsupported data.
Example: VAT/taxes on goods and consumer choice
When a tax increases the price of a good:
- if demand is inelastic, revenue may rise and quantity falls less
- if demand is elastic, consumption drops more
Consumers might shift to cheaper brands or substitutes, which affects firm demand and competitive dynamics.
Example: TVET and skills
A skills training program (often provided via TVET colleges or partnerships) can reduce structural unemployment by improving job matching and employability. In business terms, firms benefit from more reliable labour supply and reduced training costs.
5.6 Mini-Practice Sets (Examination-Style)
These practice items are structured like typical test and exam questions. They show the kind of reasoning you should demonstrate. (No step is intentionally incomplete; use them to rehearse full-mark answers.)
Practice 1: Demand shift and equilibrium
Question: The number of students in Johannesburg increases, raising demand for student accommodation. Using demand and supply, explain the effect on rent prices and accommodation availability.
What a full-mark answer should include:
- Identify an increase in demand (non-price determinant: number of buyers).
- Draw demand shifting right.
- State: equilibrium rent (price) increases; quantity of accommodation rented increases.
- If supply is inelastic (housing capacity limited short-run), price rises more than quantity.
Practice 2: Elasticity and revenue
Question: A retailer increases the price of a product. The retailer’s sales revenue rises after the price increase. What can you infer about demand elasticity?
Expected reasoning:
- Revenue rises when price increases and quantity demanded falls less than proportionally.
- That implies demand is inelastic (|PED| < 1).
Practice 3: Break-even calculation
Question: A company has fixed costs of R30 000 per month. Variable cost per unit is R12. The selling price is R25 per unit. Calculate the break-even number of units.
Solution outline:
- TR = 25Q
- TC = 30 000 + 12Q
- 25Q = 30 000 + 12Q
- 13Q = 30 000
- Q = 30 000 / 13 ≈ 2 307.69 → approximately 2 308 units
- Interpretation: at Q ≈ 2 308, accounting profit ≈ 0.
Practice 4: Opportunity cost in decision-making
Question: A student uses their own laptop for tutoring. The laptop could have been rented for R200 per day. Should the student include this amount in costs when deciding whether tutoring is worthwhile?
Expected reasoning:
- Yes, because the rent forgone is an opportunity cost (economic cost), even though it is not an explicit cash payment.
5.7 Exam Writing Style for Economics & Business
To maximize marks, adopt an exam-writing style that graders can easily follow.
Use clear signalling phrases
- “Holding other factors constant…”
- “This causes a shift in demand…”
- “Therefore equilibrium price increases/decreases…”
- “Because demand is inelastic, revenue rises/falls…”
Keep answers structured
For each sub-question:
- Answer question directly first (one sentence)
- Support with reasoning (2–4 sentences)
- If diagrams/calculations: state final conclusion last
Quantitative precision
If a question includes numbers, show arithmetic. If it is qualitative, don’t invent numbers.
Consolidated Key Concepts (Quick Reference)
This section consolidates the major topics covered above in a compact format for revision.
Demand and Supply
- Law of demand: price ↑ → quantity demanded ↓ (ceteris paribus)
- Demand determinants: income, tastes, substitutes/complements, expectations, number of buyers
- Change in quantity demanded vs shift in demand
- Law of supply: price ↑ → quantity supplied ↑
- Supply determinants: input prices, technology, taxes/subsidies, number of sellers, expectations
Equilibrium and Policy
- Equilibrium: Qd = Qs
- Price controls:
- Ceiling below equilibrium → shortage
- Floor above equilibrium → surplus
Elasticity
- |PED| > 1 elastic, |PED| < 1 inelastic
- Revenue effects:
- elastic demand → price ↑ revenue ↓
- inelastic demand → price ↑ revenue ↑
- Tax incidence depends on relative elasticities
Firm Costs and Decisions
- TC = FC + VC
- MC governs optimal output logic (in competitive settings P = MC)
- Economic profit includes opportunity costs
- Shutdown when price < AVC (short-run logic)
Macro for Business
- GDP and real vs nominal growth
- Inflation reduces real purchasing power; affects costs and interest rates
- Unemployment impacts labour markets and consumer demand
- Interest rate and exchange rate risks affect investment and costs
- Fiscal/monetary policy changes affect business planning
Final Revision Checklist for EKN0A11
Before exams, ensure you can do the following without hesitation:
- Draw and interpret demand–supply diagrams with correct shift directions.
- Explain equilibrium and what happens with excess demand/supply.
- Compute and interpret break-even in basic cost-revenue problems.
- Use elasticity rules for revenue and tax incidence.
- Distinguish economic vs accounting profit and incorporate opportunity cost.
- Connect micro concepts (costs, pricing, demand) to macro conditions (inflation, unemployment, interest rates).
- Answer structured multi-part scenarios clearly, using economic mechanisms rather than memorized phrases.
With these competencies, EKN0A11 becomes less about memorizing terms and more about consistently applying economic reasoning to business and market problems—exactly the skill South African economics module assessments typically reward.
