Show model answer and explanation
movement along
The other demand conditions are held fixed.
Class 12 · English Medium · Cambridge · Economics
Markets, demand and supply
Use demand and supply to explain a price change under stated conditions.
Shared cross-level core and stretch unit. Start with the core questions, then use the stretch example for deeper work. The same unit is available in related class and board pathways; it is not a full grade-specific or examination-specification course. A teacher should select the appropriate depth and further topics.
Learn the idea
Demand relates quantities buyers are willing and able to buy to prices, other things equal. A price change moves along a demand curve; income or preferences can shift it. Supply reflects sellers’ quantities at prices. Equilibrium in the simple model occurs where planned quantities match.
Worked example
If demand increases while supply is unchanged and upward sloping, equilibrium price and quantity tend to rise in the model. A change in price alone is not described as a shift of demand.
- Identify what changed first.
- Decide movement or shift.
- Trace the new intersection and state assumptions.
Stretch example
Price elasticity of demand compares proportional quantity response with proportional price change. Using the initial-value method, a 10% quantity fall after a 5% price rise gives elasticity −2; its magnitude 2 means a proportionally larger quantity response in that example.
Your written practice
Show your working on paper and enter your answer here. If it does not match, compare the model and try again.
Show model answer and explanation
20
50−30 = 20.
Show model answer and explanation
20
100−2P=20+2P gives P=20.
Write in your own words. A guardian or teacher should review this response.
Show model answer and explanation
It can lower unit costs or allow more output at each price.
Explain a supply-side mechanism.
Write in your own words. A guardian or teacher should review this response.
Show model answer and explanation
Supply may have fallen or several factors may have changed.
Give an alternative explanation.
Show model answer and explanation
2
12/6 = 2.
Write in your own words. A guardian or teacher should review this response.
Show model answer and explanation
Different percentage bases and adjustment periods can change the result.
Explain what the comparison depends on.
Market case
Draw a supply-demand diagram for a fictional crop after a supply disruption.
Review with a guardian or teacher
- Label the initial and shifted curves.
- Trace price and quantity.
- Avoid claiming a real forecast from the diagram alone.
Keep your work on paper or in a local file. This page does not upload it or automatically grade the project.
Teacher-led lessons, schedules and prices for this outline are upcoming. You can use any starter practice above now without booking.
Your next step
Solo practice works without an account. Sign in to save a practice record to your learner profile.
Keep practising
Exact lesson links and related activities are labelled separately. Return-to-course links retain your selected learning path.