GCSE Maths: Conditional Probability
Solve probability problems involving dependent events and without replacement. Practise it with adaptive questions for AQA, Edexcel, OCR and Eduqas.
What you need to know
The concepts examiners test on conditional probability, and what each one is really asking.
Where marks get lost
The exam technique that separates a correct method from a correct answer.
- Using the same probabilities for both picks (forgetting 'without replacement' changes totals)
- Not reducing the total by 1 after the first pick
- Reducing both the specific count AND the total incorrectly
- Confusing 'with' and 'without' replacement
Conditional Probability questions students ask
Is Conditional Probability on the Foundation paper?
Yes. Conditional Probability appears at both Foundation and Higher tier, though Higher papers take it further.
What should I know before starting Conditional Probability?
It builds on Basic probability and Tree diagrams and Multiplying and simplifying fractions. If those feel shaky, practise them first — Conditional Probability questions assume them.
What is the most common mistake in Conditional Probability?
Using the same probabilities for both picks (forgetting 'without replacement' changes totals).
Which exam boards cover Conditional Probability?
All four we support — AQA, Edexcel, OCR and Eduqas. GCSE Maths subject content is set by the DfE, so the topic is common to every board; what changes is the paper structure and the grade boundaries.