S5 Economics Practice Paper: Demand, Supply, Elasticity, Market Structure, National Income And Policy (100 Marks)

S5 Economics Practice Paper: Demand, Supply, Elasticity, Market Structure, National Income and Policy (100 marks)

2026-11-12

S5 Economics – Demand, Elasticity and Policy

S5 Economics paper: 6 questions, 17 parts, 100 marks, 60 minutes. Covers demand and supply, elasticity, market structure, GDP, inflation, unemployment and policy.

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Paper details　S5 Economics practice paper with model answers on demand and supply, elasticity, market structure, GDP and policy.

Part 1: Demand, supply and price ceiling (20 marks)

Three questions. Show all steps and units.

#	Question	Answer and marking notes
1	(a) In a market, demand is Qd = 240 – 6P and supply is Qs = 4P – 60. Find the equilibrium price and quantity.	Answer: At equilibrium Qd = Qs, so 240 – 6P = 4P – 60, giving 10P = 300, hence P = 30; substituting gives Q = 60 units. (3 marks price, 3 marks quantity)
2	(b) If the government sets a price ceiling at P = 20, find quantity demanded, quantity supplied and the shortage, and explain the cause.	Answer: At P = 20, Qd = 240 – 120 = 120 units and Qs = 80 – 60 = 20 units, so the shortage is 120 – 20 = 100 units. The ceiling is below the equilibrium price, so quantity demanded exceeds quantity supplied and excess demand appears. (2 marks each for demand, supply, shortage; 2 marks explanation)
3	(c) Assuming a linear demand curve, find the consumer surplus at equilibrium.	Answer: Demand is zero when P = 240 / 6 = 40. Consumer surplus = 0.5 x (40 – 30) x 60 = 300. (2 marks formula, 2 marks substitution, 2 marks value)

Part 2: Elasticity and tax incidence (18 marks)

Three questions. Show percentage calculations.

#	Question	Answer and marking notes
4	(a) The price of a good falls from 50 to 40 and quantity demanded rises from 80 to 104 units. Find the price elasticity of demand (absolute value) and state whether demand is elastic, unit elastic or inelastic.	Answer: Change in quantity = (104 – 80) / 80 = 30% and change in price = (40 – 50) / 50 = -20%, so elasticity = 30% / 20% = 1.5. Since it exceeds 1, demand is elastic. (2 marks percentages, 2 marks elasticity, 2 marks conclusion)
5	(b) In an income elasticity test, income rises by 5% and quantity demanded rises by 8%. Find the income elasticity and state the type of good.	Answer: Income elasticity = 8% / 5% = 1.6. Being greater than 1, the good is a normal good of the luxury type. (3 marks calculation, 3 marks classification)
6	(c) The government imposes a per-unit tax of 30. Price elasticity of demand is 2 and price elasticity of supply is 0.5. Find the tax borne per unit by consumers and by producers.	Answer: Consumers bear 0.5 / (2 + 0.5) = 0.2 of the tax, i.e. 0.2 x 30 = 6. Producers bear 30 – 6 = 24 per unit. (3 marks share, 3 marks both amounts)

Part 3: Perfect competition and monopoly (16 marks)

Two questions. State the profit-maximising condition.

#	Question	Answer and marking notes
7	(a) A perfectly competitive firm has MC = 3Q, the market price is 60 and fixed cost is 450. Find the profit-maximising output, total revenue and profit.	Answer: Profit is maximised where P = MC, so 60 = 3Q gives Q = 20. Total revenue = 60 x 20 = 1200, variable cost = 1.5 x 20 x 20 = 600, hence profit = 1200 – 600 – 450 = 150. (3 marks output, 2 marks revenue, 2 marks cost, 1 mark profit)
8	(b) A monopolist faces demand P = 100 – 2Q, with constant marginal cost 28 and average cost 30. Find output, price and profit.	Answer: Total revenue = 100Q – 2Q^2, so marginal revenue = 100 – 4Q. Setting MR = MC gives 100 – 4Q = 28, so Q = 18 and P = 100 – 36 = 64. Profit = (64 – 30) x 18 = 612. (2 marks each for MR, output, price, profit)

Part 4: GDP and economic growth (16 marks)

Three questions. All amounts are in billion dollars.

#	Question	Answer and marking notes
9	(a) Compute GDP by the expenditure approach: private consumption 600, investment 180, government spending 150, exports 300 and imports 230.	Answer: GDP = 600 + 180 + 150 + 300 – 230 = 1000. (3 marks formula, 3 marks value)
10	(b) If net factor income from abroad is -20, find GNP.	Answer: GNP = GDP + net factor income from abroad = 1000 + (-20) = 980. (2 marks formula, 2 marks value)
11	(c) Year 2 nominal GDP is 1050 with a GDP deflator of 105; year 1 real GDP was 960. Find year 2 real GDP and the growth rate (percentage, two decimal places).	Answer: Real GDP = 1050 / 105 x 100 = 1000, so the growth rate = (1000 – 960) / 960 x 100% = 4.17%. (3 marks each)

Part 5: CPI, real wage and unemployment (15 marks)

Three questions. Give percentages to two decimal places.

#	Question	Answer and marking notes
12	(a) The CPI basket weights are food 40%, housing 35% and transport 25%. Over the period food prices rise 10%, housing 6% and transport 3%. Find the weighted inflation rate.	Answer: Weighted inflation = 0.4 x 10% + 0.35 x 6% + 0.25 x 3% = 4% + 2.1% + 0.75% = 6.85%. (2 marks per term, 1 mark total)
13	(b) Nominal wages rise 9% over the same period. Find the percentage change in the real wage.	Answer: Real wage change = (1.09 / 1.0685 – 1) x 100% = 2.01%, a real rise of 2.01%. (2 marks formula, 2 marks value)
14	(c) The labour force is 5.00 million and employment is 4.60 million. Find the number of unemployed and the unemployment rate.	Answer: Unemployed = 500 – 460 = 40 (in ten thousands); unemployment rate = 40 / 500 x 100% = 8%. (2 marks each)

Part 6: Money supply and fiscal policy (15 marks)

Three questions. Show the multiplier formulae.

#	Question	Answer and marking notes
15	(a) The required reserve ratio is 20% and a customer deposits 80. Find the money multiplier and the maximum total deposits created.	Answer: Money multiplier = 1 / 0.2 = 5, so total deposits = 80 x 5 = 400. (3 marks each)
16	(b) Potential output is 1200, actual output is 1140 and the expenditure multiplier is 4. Find the output gap and the required increase in government spending.	Answer: Output gap = 1200 – 1140 = 60, so the required spending increase is 60 / 4 = 15. (2 marks gap, 3 marks injection)
17	(c) The marginal propensity to consume is 0.8 and government spending rises by 20. Find the expenditure multiplier and the change in equilibrium output.	Answer: Expenditure multiplier = 1 / (1 – 0.8) = 5, so output changes by 20 x 5 = 100. (2 marks each)

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