> ## Content Index
> Fetch the complete content index at: https://www.a-level-maths-tutor.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# A-Level Maths | Probability
- URL: https://www.a-level-maths-tutor.com/a-level-maths-probability/
- Published: 2026-03-18T09:51:50.000Z
- Updated: 2026-04-23T10:58:27.000Z
- Author: Jaisul Naik

### What does P(A) mean?

P(A) is the probability of A happening

### What does P(A') mean?

P(A') is the probability of A not happening

### What does P(A∩B) mean?

P(A∩B) is the probability of A and B happening

### What does P(AUB) mean?

P(AUB) is the probability of only A happening, or only B happening, or both A and B happening

### What does P(A|B) mean?

 P(A|B) is the probability of A happening given that we know B is also happening.

### What does independent mean?

A and B are independent if **P(A∩B) = P(A) x P(B)**

### What does mutually exclusive mean?

A and B are mutually exclusive if **P(A∩B) = 0**

## Venn Diagrams

### Question 1

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.40.36@2x.png)

### Question 2

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.41.17@2x.png)

### Question 3

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.41.45@2x.png)

## Conditional Probability in Venn Diagrams

### Question 4

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.46.16@2x.png)

### Question 5

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/image-1.png)

### Question 6

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.47.11@2x.png)

## Probability Tree Diagrams

### Question 8

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.53.53@2x.png)

### Question 9

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.55.38@2x.png)

### Question 10

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.56.19@2x.png)

## Conditional Probability in Tree Diagrams

### What is the formula for P(A|B)?

**P(A|B) = P(A∩B)/P(B)**

### Question 13

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.58.59@2x.png)

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.59.15@2x.png)

### Question 14

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.59.34@2x.png)

### Question 15

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-13.59.59@2x.png)

### Question 16

![](https://storage.ghost.io/c/37/0e/370e4698-c6d5-4470-8b24-7d14723fff86/content/images/2026/02/CleanShot-2026-02-13-at-14.00.12@2x.png)