General Certificate of Secondary Education (GCSE) Maths Practice Exam 2026 - Free Maths Practice Questions and Study Guide

To calculate the probability of two dependent events A and B occurring together, you use the formula for conditional probability. When events are dependent, the occurrence of A affects the probability of B occurring. This relationship is expressed mathematically as:

P(A and B) = P(A) x P(B given A)

In this formula:

- P(A) represents the probability of event A occurring.

- P(B given A) denotes the probability of event B occurring after A has already occurred, reflecting the dependency between the two events.

By multiplying these two probabilities, you take into account how the occurrence of A influences B, which is essential in calculating the joint probability of these dependent events. This method effectively captures the necessary relationship between the events, ensuring an accurate calculation.

The other choices do not appropriately represent the relationship between dependent events, which is why they would not yield a correct calculation for P(A and B).