NumberKey Facts

Essential Growth & Decay Formulas

Part of Growth & DecayGCSE Mathematics

This key facts covers Essential Growth & Decay Formulas within Growth & Decay for GCSE Mathematics. Revise Growth & Decay in Number for GCSE Mathematics with 12 exam-style questions and 22 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 2 of 8 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 8

Practice

12 questions

Recall

22 flashcards

Essential Growth & Decay Formulas

Type Formula Variables When to Use
Exponential Growth N = N₀ × (1 + r)ⁿ N₀ = initial, r = rate, n = time periods Population, compound interest, bacteria
Exponential Decay N = N₀ × (1 - r)ⁿ N₀ = initial, r = rate, n = time periods Radioactivity, depreciation, medicine
Half-life N = N₀ × (0.5)ⁿ n = number of half-life periods Radioactive decay, drug elimination
Doubling Time N = N₀ × 2ⁿ n = number of doubling periods Bacterial growth, compound interest

Keep building this topic

Read this section alongside the surrounding pages in Growth & Decay. That gives you the full topic sequence instead of a single isolated revision point.

Practice Questions for Growth & Decay

A quantity increases by 8% each year. Which multiplier should be used for each year?

  • A. 0.08
  • B. 0.92
  • C. 1.08
  • D. 1.8
1 markfoundation

Explain the difference between simple interest and compound interest.

2 marksstandard

Quick Recall Flashcards

What is the formula for exponential decay?
N = N₀ × (1 - r)ⁿ Where: N = final amount N₀ = initial amount r = decay rate (as decimal) n = number of time periods
What is the formula for half-life decay?
N = N₀ × (0.5)ⁿ Where: N = remaining amount N₀ = initial amount n = number of half-life periods

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