🎲 Probability

Conditional probability

Learn conditional probability with a GCSE-style explanation, help guide, worked example, practice question and flashcards.

ProbabilityGCSE25 XP completion3 flashcards

Global XP

Level 1

0 / 100 XP

1. Explanation

Key idea

Conditional probability is part of probability and appears often in KS3–GCSE maths.
Conditional probability depends on what has already happened.
Use the worked model, help guide, interactive question and flashcards to practise conditional probability until the steps feel automatic.

Shopping, sport, travel, science, design and everyday decisions all use this skill.

2. Visual

Understand the key idea → follow the help guide → practise a question → check your method → build speed with flashcards.

3. Help guide

Learn the rule: Conditional probability depends on what has already happened.
Worked model: Update the sample space after the condition. Count favourable outcomes. Write the new probability.
Try the interactive question without looking at the answer first.
Use the flashcards to test the rule, the method and a common check.

4. Worked examples

Answer: Without replacement changes the second probability

5. Interactive questions

6. Flashcards

Flip each card, then choose whether you know it or need more practice.

0 mastered

FrontRule for Conditional probability

BackConditional probability depends on what has already happened.

FrontExample answer: There are 3 red and 2 blue counters. One red is removed. What is P(red next)?

BackAfter a red is removed, 4 counters remain and 2 are red. P(red) = 2/4 = 1/2.

FrontCommon check for Conditional probability

BackCheck units/notation, compare with an estimate, and make sure the answer matches the question.

7. Finish

When you have read the examples, tried the question and reviewed flashcards, claim your topic completion XP.