Method: Exponential Problems

Part of Compound Interest · Section 3 of 6

Deep DiveUnit: Ratio & ProportionGCSE

This deep dive covers Method: Exponential Problems 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 3 of 6 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

Method: Exponential Problems

1 Identify: growth (+r) or decay (-r)?

2 Find the multiplier: (1+r) or (1-r)

3 Write formula with starting value and time periods

4 Calculate using power button on calculator

Practice questions for Compound Interest

Which formula correctly calculates the amount A after compound interest at rate r% per year for n years on principal P?

A. A = P × (1 + r/100) × n
B. A = P × (1 + r/100)^n
C. A = P + P × r/100 × n
D. A = P × r^n / 100

1 markfoundation

£2,000 is invested for 4 years. - Account A pays 5% simple interest per year. - Account B pays 4.5% compound interest per year. Which account gives more money after 4 years? Show all working.

3 marksstandard

Quick recall flashcards

Growth vs Decay

Growth: multiply by (1+r). Decay: multiply by (1-r). The multiplier is raised to the power of n (time periods).

Exponential Decay

N = N₀ × (1 - r)^t for decay rate r

Key Facts

Worked Example 1: Population Growth

12 questions on Compound Interest — practise free

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