Worked Example 1: Population Growth
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 6 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 6
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)
Keep building this topic
Read this section alongside the surrounding pages in Compound Interest. That gives you the full topic sequence instead of a single isolated revision point.
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?
£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.
Quick Recall Flashcards
12 questions on Compound Interest — practise free
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