GCSE · Percentages & growth

Compound growth and decayExam-style questions

Why repeated percentage change is a power of the multiplier, how compound interest differs from simple interest, and how to build growth and decay models.

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19 questions · GCSE (Higher) level · mark scheme and worked solution on each · no sign-up to try

DifficultyAll Level 1 Level 2 Level 3 Level 4 Level 5

1
£2500 is invested at 4.2% compound interest per year. Work out the smallest number of complete years for the value of the investment to first exceed £3000.
Level 5 · 3 marksTry it
2
£ $5000$ is invested at $r\%$ compound interest per year.

After $2$ years the investment is worth £ $5618$ .

Work out the value of $r$ .
Level 5 · 3 marksTry it
3
A fishery estimates its fish stock at $40\,000$ . The stock is falling by $8\%$ each year.

Work out the smallest number of complete years until the stock first falls below $30\,000$ .
Level 5 · 3 marksTry it