The events A and B are such that P(A)=320\displaystyle P(A) = \frac{3}{20}P(A)=203, P(A∩B)=120\displaystyle P(A \cap B) = \frac{1}{20}P(A∩B)=201, P(A∣B)=514\displaystyle P(A|B) = \frac{5}{14}P(A∣B)=145.
Verify P(B)=750\displaystyle P(B) = \frac{7}{50}P(B)=507
Verify P(A∪B)=625\displaystyle P(A \cup B) = \frac{6}{25}P(A∪B)=256
Verify P(B∣A′)=985\displaystyle P(B|A') = \frac{9}{85}P(B∣A′)=859
368 exam-style questions on Edexcel A Level Maths Conditional Probability, covering 2.1 Set Notation, 2.2 Conditional Probability, 2.3 Conditional Probabilities in Venn Diagrams, 2.4 Probability Formulae, and 2.5 Tree Diagrams. Each one has a worked solution and a mark scheme showing where the marks go.