Ratio & ProportionStudy Notes

Worked Example 1: Population Growth

Part of Compound Interest — GCSE Mathematics

This study notes covers Worked Example 1: Population Growth 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 4 of 5 in this topic. Use this study notes to connect the idea to the wider topic before moving on to questions and flashcards.

Topic position

Section 4 of 5

Practice

12 questions

Recall

4 flashcards

Worked Example 1: Population Growth

A colony of 500 bacteria grows by 20% each hour. How many after 5 hours?

Step 1 Identify type and multiplier

Growth, so multiplier = 1 + 0.20 = 1.2

Step 2 Write formula

y = 500 × 1.2⁵

Step 3 Calculate

y = 500 × 2.48832 = 1244 bacteria (to nearest whole)

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

Worked Example 1: Population Growth

Worked Example 1: Population Growth

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Practice Questions for Compound Interest

Quick Recall Flashcards

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