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Proportion problems are a staple of the Edexcel GCSE Mathematics (1MA1) specification. They test your ability to scale quantities up or down, compare value for money, and work with the unitary method. Proportion questions appear on all three papers and range from straightforward scaling to multi-step best-buy problems.
Two quantities are in proportion if they increase (or decrease) at the same rate. When one doubles, the other doubles; when one is halved, the other is halved.
| Term | Meaning | Example |
|---|---|---|
| Direct proportion | As one increases, the other increases at the same rate | More hours worked = more pay |
| Unitary method | Finding the value of one unit first, then scaling | Cost of 1 item, then cost of n items |
| Scaling | Multiplying all quantities by the same factor | Recipe for 4 scaled to recipe for 6 |
The unitary method is one of the most reliable approaches for proportion questions on Paper 1 (non-calculator).
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