What this practice covers
These questions are drawn from past IB Economics papers and filtered to supply. You answer, you find out immediately whether you were right, and you get the reasoning for the correct option and for each distractor. Wrong answers go to a mistakes locker so you can come back to exactly those.
Practice is free. You need an account only so your progress and your mistakes are still there next time.
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What examiners see students get wrong here
These are the errors that cost marks on supply, taken from our own topic notes. Read them before you practise and you will recognise the traps in the questions.
- Confusing a shift (cost, technology, tax) with a movement along (own-price change).
- Treating an indirect tax as a demand-side change. It raises firms' costs and shifts supply.
- Writing that a price rise "increases supply", it increases quantity supplied.
- Shifting supply for a change in consumer incomes or tastes, which are demand factors.
- Unlabelled diagrams, or shifting the curve without marking the new equilibrium.
- Forgetting that a per-unit tax shifts supply vertically by the tax amount, not by an arbitrary distance.
- Claiming price rises by the full amount of a per-unit tax.
- (HL) Extending the supply curve below the price at which Qs = 0, into negative quantities.
Revise it first
If any of the above is unfamiliar, work through the notes before practising: Supply revision notes.