The interaction of demand and supply
2.4What the syllabus asks of you
- definition of market equilibrium and disequilibrium
- effects of shifts in demand and supply curves on equilibrium price and quantity
- relationships between different markets: joint demand (complements)
- relationships between different markets: alternative demand (substitutes)
- relationships between different markets: derived demand
- relationships between different markets: joint supply
- functions of price in resource allocation; rationing, signalling (transmission of preferences) and incentivising
Drill this topic
Every question on The interaction of demand and supply, untimed, marked as you go.
Make a worksheet
Choose the years and how many questions, then print it with the answers on separate pages.
59 questions
1May / June 2026 · Paper 14 · Q10Show mark scheme →
A$5
B$8
C$15
D$20
Mark scheme
2May / June 2026 · Paper 14 · Q15Show mark scheme →
A1 and 2
B1 and 4
C2 and 3
D3 and 4
Mark scheme
3Oct / Nov 2025 · Paper 11 · Q6Show mark scheme →
Awhen ceteris paribus no longer applies
Bwhen quantity demanded equals quantity supplied
Cwhen quantity demanded is equal to price
Dwhen supply can no longer expand
Mark scheme
4Oct / Nov 2025 · Paper 12 · Q11Show mark scheme →
Aprice: decrease; sales: decrease
Bprice: decrease; sales: increase
Cprice: increase; sales: decrease
Dprice: increase; sales: increase
Mark scheme
5Oct / Nov 2025 · Paper 14 · Q9Show mark scheme →
Aproviding incentives for government intervention to reduce income inequality
Bremoving shortages by creating incentives for market prices to fall
Cremoving surpluses by creating incentives for market prices to rise
Dsignalling changes in market conditions to producers and consumers
Mark scheme
6May / June 2025 · Paper 11 · Q6Show mark scheme →
Ato act as a signal to firms when allocating resources
Bto maximise consumer surplus
Cto provide an incentive to firms to produce goods
Dto ration scarce resources
Mark scheme
7May / June 2025 · Paper 12 · Q10Show mark scheme →
AFarmers and honeyguide birds are rival consumers.
BWild honey and beeswax are free goods.
CWild honey and beeswax are in joint supply.
DWild honey is the opportunity cost of beeswax.
Mark scheme
8May / June 2025 · Paper 13 · Q8Show mark scheme →
A
B
C
D
Mark scheme
9May / June 2025 · Paper 13 · Q10Show mark scheme →
A$45
B$40
C$35
D$30
Mark scheme
10Oct / Nov 2024 · Paper 12 · Q11Show mark scheme →
AProducers of good X adopt new technology.
BProducers of good X receive a subsidy.
CSome firms stop production of good X.
DThe tax on the production of good X is cut.
Mark scheme
11May / June 2024 · Paper 11 · Q11Show mark scheme →
AA
BB
CC
DD
Mark scheme
12May / June 2024 · Paper 13 · Q7Show mark scheme →
Aequilibrium price falls, equilibrium quantity uncertain
Bequilibrium price rises, equilibrium quantity uncertain
Cequilibrium price uncertain, equilibrium quantity falls
Dequilibrium price uncertain, equilibrium quantity rises
Mark scheme
13May / June 2024 · Paper 13 · Q9Show mark scheme →
A
B
C
D
Mark scheme
14Feb / March 2024 · Paper 12 · Q10Show mark scheme →
Aprice of bread decreases; price of buttermilk decreases
Bprice of bread decreases; price of buttermilk increases
Cprice of bread increases; price of buttermilk decreases
Dprice of bread increases; price of buttermilk increases
Mark scheme
15Oct / Nov 2023 · Paper 11 · Q7Show mark scheme →
Aa decrease in demand
Ba fall in price
Ca government minimum price
Dan increase in supply
Mark scheme
16Oct / Nov 2023 · Paper 11 · Q10Show mark scheme →
Aset a fixed price at P1
Bset a fixed price at P4
Cvary prices between P2 and P3
Dvary prices between P1 and P4
Mark scheme
17Oct / Nov 2023 · Paper 12 · Q10Show mark scheme →
AA
BB
CC
DD
Mark scheme
18Oct / Nov 2023 · Paper 12 · Q11Show mark scheme →
ADiagram A
BDiagram B
CDiagram C
DDiagram D
Mark scheme
19Oct / Nov 2023 · Paper 12 · Q12Show mark scheme →
AThe market will move from equilibrium to shortage.
BThe market will move from equilibrium to surplus.
CThe market will move from shortage to surplus.
DThe market will move from surplus to shortage.
Mark scheme
20Oct / Nov 2023 · Paper 13 · Q14Show mark scheme →
AThe excess supply will increase.
BThe market will move into an equilibrium position.
CThere will be no effect.
DThere will be excess demand.
Mark scheme
21May / June 2023 · Paper 11 · Q10Show mark scheme →
A
B
C
D
Mark scheme
22May / June 2023 · Paper 11 · Q11Show mark scheme →
A
B
C
D
Mark scheme
23May / June 2023 · Paper 11 · Q13Show mark scheme →
ASome consumers do not have effective demand.
BThe demand for medical face masks is price inelastic in the short run.
CThe price of medical face masks is fixed below the equilibrium price.
DThe supply of medical face masks is inelastic in the short run.
Mark scheme
24May / June 2023 · Paper 12 · Q5Show mark scheme →
AA price fall can show consumers that a good is becoming less popular.
BA price fall tends to persuade some producers not to stay in the market for the good.
CA price rise means consumers cannot afford to buy so much of a good.
DA price rise tends to reduce competitiveness in the market for a good.
Mark scheme
25May / June 2023 · Paper 12 · Q6Show mark scheme →
Abarley and cotton
Bgold and silver
Csoap and toothpaste
Dspinach and cabbage
Mark scheme
26May / June 2023 · Paper 12 · Q13Show mark scheme →
Awhen a decrease in the demand for a product leads to a price fall that results in some producers leaving the market
Bwhen a decrease in the demand for a product leads to some producers being unable to sell products at the current price
Cwhen a decrease in the supply of a product leads to a price rise that results in the market for the product clearing
Dwhen a decrease in the supply of a product leads to a price rise that makes it too expensive for some poorer households
Mark scheme
27May / June 2023 · Paper 13 · Q7Show mark scheme →
Aprice decrease, quantity demanded decrease, quantity supplied increase
Bprice decrease, quantity demanded increase, quantity supplied decrease
Cprice increase, quantity demanded decrease, quantity supplied increase
Dprice increase, quantity demanded increase, quantity supplied decrease
Mark scheme
28May / June 2023 · Paper 13 · Q9Show mark scheme →
AA firm can choose between producing a range of different goods.
BA good has multiple uses.
CA good is a by-product of the production process of another good.
DConsumers consider two goods as complements.
Mark scheme
29Feb / March 2023 · Paper 12 · Q11Show mark scheme →
Asupply of butter: move left along supply curve; supply of buttermilk: move left along supply curve
Bsupply of butter: move left along supply curve; supply of buttermilk: shift left of the supply curve
Csupply of butter: shift left of the supply curve; supply of buttermilk: move left along supply curve
Dsupply of butter: shift left of the supply curve; supply of buttermilk: shift left of the supply curve
Mark scheme
30Oct / Nov 2022 · Paper 11 · Q10Show mark scheme →
AA
BB
CC
DD
Mark scheme
31Oct / Nov 2022 · Paper 11 · Q13Show mark scheme →
Aincreasing the availability of loans for buying houses
Bgranting a subsidy for producers of bricks
Cremoving sales tax on electric switches
Dremoving tariffs on imports of wood
Mark scheme
32Oct / Nov 2022 · Paper 12 · Q8Show mark scheme →
AAt price OP1, UV represents the market surplus.
BAt price OP3, P3X represents the quantity that consumers are able and willing to buy.
CIf price were to fall from OP1 to OP3, the extra quantity demanded would be equal to the extra quantity supplied.
DPrice OP2 is the market equilibrium price.
Mark scheme
33Oct / Nov 2022 · Paper 12 · Q11Show mark scheme →
Aan alternative brand of smartphone
Ba personal computer (PC)
Cheadphones that can be used with a smartphone
Dthe metals used in the manufacture of a smartphone
Mark scheme
34Oct / Nov 2022 · Paper 13 · Q10Show mark scheme →
AX and Y are complements.
BX and Y are in joint supply.
CX and Y are substitutes.
DY is a derived demand from X.
Mark scheme
35Oct / Nov 2022 · Paper 13 · Q11Show mark scheme →
ADiagram A: price P_F below the intersection of downward-sloping D and vertical S at quantity 40 000
BDiagram B: price P_F below the intersection of downward-sloping D and vertical S at quantity 40 000
CDiagram C: price P_F above the intersection of downward-sloping D and upward-sloping S, with quantity 40 000 at the intersection
DDiagram D: price P_F below the intersection of downward-sloping D and upward-sloping S, with quantity 40 000 at the intersection
Mark scheme
36Oct / Nov 2022 · Paper 13 · Q13Show mark scheme →
Aa decrease in demand that is larger than a decrease in supply
Ba decrease in demand that is smaller than a decrease in supply
Can increase in demand that is larger than an increase in supply
Dan increase in demand that is smaller than an increase in supply
Mark scheme
37Oct / Nov 2022 · Paper 13 · Q14Show mark scheme →
Aan increase in demand and an increase in supply
Ban increase in demand and a decrease in supply
Ca decrease in demand and an increase in supply
Da decrease in demand and a decrease in supply
Mark scheme
38May / June 2022 · Paper 11 · Q11Show mark scheme →
Awhen the government bans advertising
Bwhen the government maintains an effective maximum price
Cwhen there is a limited supply of the good
Dwhen there is a powerful company able to set the market price
Mark scheme
39May / June 2022 · Paper 11 · Q12Show mark scheme →
Afalls / falls
Bfalls / rises
Crises / falls
Drises / rises
Mark scheme
40May / June 2022 · Paper 12 · Q7Show mark scheme →
AThey allocate resources to the greatest needs.
BThey ensure that goods and services are distributed equally.
CThey are both significant in setting the market price.
DThey ensure that everyone can benefit from the good or service provided.
Mark scheme
41May / June 2022 · Paper 12 · Q12Show mark scheme →
APrice determines the supply of public goods.
BPrice operates in the markets for both goods and factors of production.
CPrice recognises consumers' ability to pay rather than consumers' needs.
DPrice signals to producers which goods are most profitable.
Mark scheme
42May / June 2022 · Paper 12 · Q13Show mark scheme →
APrice is likely to change.
BSupply is equal to demand.
CThe government must intervene.
DThere must be shortages.
Mark scheme
43May / June 2022 · Paper 12 · Q16Show mark scheme →
Aprice of electricity falls; sales of electricity falls
Bprice of electricity falls; sales of electricity rises
Cprice of electricity rises; sales of electricity falls
Dprice of electricity rises; sales of electricity rises
Mark scheme
44May / June 2022 · Paper 13 · Q5Show mark scheme →
ADiagram A: downward-sloping demand curve with vertical supply curve
BDiagram B: downward-sloping demand curve with upward-sloping supply curve
CDiagram C: upward-sloping supply curve with vertical demand curve
DDiagram D: downward-sloping demand curve with horizontal supply curve
Mark scheme
45May / June 2022 · Paper 13 · Q8Show mark scheme →
Aprice: fall; quantity: uncertain
Bprice: rise; quantity: increase
Cprice: uncertain; quantity: increase
Dprice: uncertain; quantity: uncertain
Mark scheme
46May / June 2022 · Paper 13 · Q10Show mark scheme →
Agood Y price: fall, sales: fall; good Z price: rise, sales: rise
Bgood Y price: fall, sales: rise; good Z price: rise, sales: rise
Cgood Y price: rise, sales: fall; good Z price: fall, sales: rise
Dgood Y price: rise, sales: rise; good Z price: fall, sales: fall
Mark scheme
47May / June 2022 · Paper 14 · Q5Show mark scheme →
Adecrease / decrease
Bincrease / decrease
Cdecrease / increase
Dincrease / increase
Mark scheme
48May / June 2022 · Paper 14 · Q13Show mark scheme →
AA
BB
CC
DD
Mark scheme
49Feb / March 2022 · Paper 12 · Q13Show mark scheme →
AX and Y are complements.
BX and Y are demerit goods.
CX and Y are in joint supply.
DX and Y are substitutes.
Mark scheme
50Oct / Nov 2021 · Paper 11 · Q22Show mark scheme →
Adecreases; improves
Bdecreases; worsens
Cincreases; improves
Dincreases; worsens
Mark scheme
51Oct / Nov 2021 · Paper 12 · Q8Show mark scheme →
AWhen the price of a product is falling, firms will allocate less resources to its production.
BWhen the price of a product is falling, the government can set an effective minimum price.
CWhen the price of a product is rising, firms will expand production of the product to make profits.
DWhen the price of a product is rising, some consumers will no longer be able to buy it.
Mark scheme
52Oct / Nov 2021 · Paper 13 · Q6Show mark scheme →
AX and Y are complements.
BX and Y are in joint supply.
CX and Y are substitutes.
DY is a derived demand from X.
Mark scheme
53Oct / Nov 2021 · Paper 13 · Q11Show mark scheme →
Aa decrease in both the demand for and the supply of the good
Ban increase in both the demand for and the supply of the good
Can increase in consumer incomes, and a decrease in the supply of the good
Dan increase in the price of a complement to the good, and an increase in the supply of the good
Mark scheme
54Oct / Nov 2021 · Paper 13 · Q12Show mark scheme →
Aimpose an indirect tax of $2 per kg on kiwifruit
Bpurchase the entire supply at $3 per kg and sell at $2 per kg
Cset a maximum price of $3 per kg
Dsubsidise kiwifruit production by $2 per kg
Mark scheme
55May / June 2021 · Paper 11 · Q6Show mark scheme →
Awhen a good has a number of close substitutes
Bwhen a good is an inferior good
Cwhen the demand for a good is perfectly inelastic
Dwhen the quantity of a good is in fixed supply
Mark scheme
56May / June 2021 · Paper 11 · Q11Show mark scheme →
AX, Q, R
BX, R, Q
CX, S, R
DX, T, S
Mark scheme
57May / June 2021 · Paper 12 · Q10Show mark scheme →
Adecrease / decrease
Bdecrease / increase
Cincrease / decrease
Dincrease / increase
Mark scheme
58Feb / March 2021 · Paper 12 · Q7Show mark scheme →
Aan increase in the price of a complement
Ban increase in the price of a substitute
Cthe imposition of a minimum price of 60 cents by a government
Dthe imposition of an indirect tax on suppliers
Mark scheme
59Feb / March 2021 · Paper 12 · Q12Show mark scheme →
Agrant a subsidy to farmers equivalent to PP1
Bimpose an indirect tax equivalent to PP2
Cplant more wheat to increase supplies to 40 million tonnes
Duse existing stocks of wheat to increase supplies by 20 million tonnes
Mark scheme