This key facts covers Key Facts within Compound Interest for GCSE Mathematics. Revise Compound Interest in Ratio & Proportion for GCSE Mathematics with 12 exam-style questions and 4 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 2 of 5 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 2 of 5
Practice
12 questions
Recall
4 flashcards
Key Facts
| Growth Formula | y = a × (1 + r)ⁿ |
| Decay Formula | y = a × (1 - r)ⁿ |
| a = | Initial amount (starting value) |
| r = | Rate as a decimal (e.g., 5% = 0.05) |
| n = | Number of time periods |
| Multiplier | Growth: (1+r), Decay: (1-r) |