Cambridge IGCSE Economics: Equilibrium, disequilibrium and price changes (0455) – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

This set tests sections 2.5 and 2.6 of the Cambridge IGCSE Economics 0455 syllabus for examination in 2026. All names and figures are invented. Teaching is in the study guide and the revision notes. Other links: the Cambridge IGCSE Economics hub, the printable checklist and the free diagnostics.

Questions

1. Define market disequilibrium. [2]

2. The table shows the market for cut flowers in City C (invented), in bunches per week. Prices are in dollars per bunch.

Price	Quantity demanded	Quantity supplied
6	600	200
8	500	300
10	400	400
12	300	500
14	200	600

(a) State the equilibrium price and the equilibrium quantity. [2] (b) Calculate the surplus or shortage at a price of 14, and say which it is. [2] (c) Calculate the value of weekly sales at equilibrium. [1]

3. Using the table in question 2, explain how the market adjusts if the price is 8. [4]

4. Cut flowers are a normal good. Explain how a rise in incomes affects the equilibrium price and sales of flowers. [4]

5. Demand for flowers increases by 100 bunches at every price. Supply is unchanged: 400 at a price of 10, 450 at 11 and 500 at 12. The original demand at 11 was 350. (a) Calculate the new quantity demanded at prices of 10 and 11. [2] (b) State the shortage at a price of 10 after the increase. [1] (c) State the new equilibrium price and quantity. [2] (d) Calculate the percentage rise in price from the original equilibrium. [1]

6. A rise in the cost of flower seed cuts supply by 100 bunches at every price. The original demand was 400 at a price of 10 and 350 at 11. The new supply is 300 at 10 and 350 at 11. (a) Calculate the shortage at a price of 10 after the fall in supply. [2] (b) State the new equilibrium price and quantity. [1] (c) Calculate the percentage change in sales from the original equilibrium of 400. [2]

7. Demand rises by 100 and supply rises by 60 bunches at every price. The new schedule is:

Price	New demand	New supply
9	550	410
10	500	460
10.40	480	480
11	450	510

(a) State the new equilibrium price and quantity. [1] (b) Calculate the percentage change in price and in sales from the original equilibrium of price 10 and 400 bunches. [2] (c) If supply had risen by 300 instead, the equilibrium would have been price 8 and 600 bunches. Explain what this shows about the effect of two shifts on price. [3]

8. Health research suggests a certain fruit is harmful, while a bumper harvest raises its supply. Analyse the effects on the price and sales of the fruit. [5]

9. A stadium in Country D (invented) has 800 seats. The table shows demand for tickets for one match.

Ticket price (dollars)	Quantity demanded
6	1,100
8	800
10	500

(a) State the price at which the market clears. [1] (b) Calculate the shortage if tickets cost 6. [2] (c) State the number of empty seats if tickets cost 10. [1] (d) Explain one problem for the organiser of keeping the price at 6. [2]

10. A scarf market in Country E (invented) has these figures, in scarves per week. Original demand is 280, 200 and 120 at prices of 8, 10 and 12. Supply is 160, 200 and 240 at those prices. Demand then rises to 400, 320 and 240. (a) State the original equilibrium price and quantity. [1] (b) State the new equilibrium price and quantity. [2] (c) Calculate the percentage change in the value of sales. [3]

11. Using the figures in questions 2, 5 and 6, evaluate whether a rise in the price of flowers is always good for flower sellers. [8]

Answers

1. A situation where the price is not the equilibrium price [1], so quantity demanded does not equal quantity supplied [1]. [2] Examiner insight: A definition that only says “demand is not equal to supply” is thin. Mention price, and mention the quantities.

2. (a) Price 10 dollars [1], quantity 400 bunches [1]. (b) Supply 600 - demand 200 [1] = a surplus of 400 bunches [1]. (c) 10 x 400 = 4,000 dollars [1]. Examiner insight: Name the condition (surplus or shortage) as well as the size. Quote units, as in “bunches per week”.

3. At a price of 8, demand is 500 and supply is 300, so there is a shortage of 200 [1]. Buyers compete for limited stock, and sellers can raise price without losing sales [1]. As price rises, quantity demanded contracts and quantity supplied extends [1]. This continues until both are 400 at a price of 10 [1]. [4] Examiner insight: Use the movement terms for the adjustment. Saying demand “decreases” describes a shift and loses the precision.

4. A rise in incomes increases demand for a normal good [1], so the demand curve shifts right [1]. At the old price there is a shortage, so price rises [1]. Supply extends along its curve, so equilibrium price and quantity are both higher [1]. [4] Examiner insight: Name the curve and the direction it moves. A chain that starts at “price rises” skips the cause.

5. (a) 400 + 100 = 500 at price 10 [1]; 350 + 100 = 450 at price 11 [1]. (b) 500 - 400 = 100 bunches [1]. (c) Price 11 [1], quantity 450 [1], where demand equals supply. (d) (11 - 10) / 10 x 100 = 10% [1]. Examiner insight: Show the subtraction in a gap calculation, and always give the percentage as change over the original.

6. (a) Original demand is 400, new supply is 300 [1], so the shortage is 100 bunches [1]. (b) Price 11, quantity 350 [1]. (c) (350 - 400) / 400 x 100 [1] = -12.5% [1]. Examiner insight: A fall needs a negative sign or the word “fall”. An answer of 12.5% with no direction may lose the final mark.

7. (a) Price 10.40, quantity 480 [1]. (b) Price: 0.40 / 10 x 100 = 4% rise [1]. Sales: 80 / 400 x 100 = 20% rise [1]. (c) Both shifts raise sales [1]. The effect on price depends on the relative size of the shifts [1]. A larger rise in supply (300) pushes price down to 8, a fall of 20%, whereas the smaller rise (60) left price slightly higher [1]. [6] Examiner insight: Say which variable is certain and which depends on shift size, and use the figures given.

8. Demand falls (curve shifts left) [1]. Supply rises (curve shifts right) [1]. Both push price down, so price falls [1]. Sales are uncertain because lower demand reduces sales and higher supply raises them [1]. The result depends on which shift is larger [1]. [5] Examiner insight: Treat the two shifts separately before combining them. Claiming a definite change in sales loses credit.

9. (a) Price 8 dollars [1]. (b) Demand 1,100 - 800 seats [1] = a shortage of 300 [1]. (c) 800 - 500 = 300 empty seats [1]. (d) Demand exceeds seats at 6, so some buyers cannot get tickets [1]. The organiser could earn more revenue by raising the price, since 800 x 8 = 6,400 dollars compared with 800 x 6 = 4,800 dollars [1]. Examiner insight: A claim of “lost revenue” earns more if supported by a comparison of figures.

10. (a) Price 10, quantity 200 [1]. (b) Price 12 [1], quantity 240 [1]. (c) Original value 10 x 200 = 2,000 [1]. New value 12 x 240 = 2,880 [1]. (2,880 - 2,000) / 2,000 x 100 = 44% rise [1]. Examiner insight: Value of sales is price times quantity. Percentage changes of price and quantity separately will not give the change in value.

11. Demand-led rise: price 11, sales 450, revenue 4,950 dollars, up 23.75% from 4,000 [1] because buyers want more and sellers sell more at a higher price [1]. Supply-led rise: price 11, sales 350, revenue 3,850 dollars, down 3.75% [1], because sales fell by 12.5% while price rose by 10% [1]. Costs also rose, so profit is squeezed further [1]. The size of each shift and how quickly sellers can respond also matter [1]. A rise in price is good for sellers when caused by higher demand, but not when caused by higher costs [1], so the answer depends on the cause, and a price rise alone is not enough to judge [1]. [8] Examiner insight: Evaluation needs a judgement that depends on a stated condition. Use calculated values from the earlier parts as evidence.

Where marks are usually lost

• Describing a shortage as a surplus.
• Using shift terms (increase or decrease) for a movement along a curve.
• Quoting the price change only when sales are also asked.
• Calculating a percentage change over the new figure, not the original.
• Giving a fall as a positive figure.
• Treating the double-shift case as if the effect on price were certain.
• Forgetting units such as bunches per week.
• Giving a conclusion in evaluation that repeats earlier points with no condition.

Next steps

• Revise from the revision notes.
• Re-read the study guide for any weak point.
• Check the Cambridge IGCSE Economics hub and tick off the printable checklist.
• Take the free 10-minute diagnostics.
• Book a free trial class.

Official syllabus

Cambridge IGCSE Economics 0455 syllabus for examination in 2026, version 2, published by Cambridge University Press & Assessment: sections 2.5 Price determination and 2.6 Price changes.