The events A and B are such that P(A)=14\displaystyle P(A) = \frac{1}{4}P(A)=41, P(A∩B)=112\displaystyle P(A \cap B) = \frac{1}{12}P(A∩B)=121, P(A∣B)=13\displaystyle P(A|B) = \frac{1}{3}P(A∣B)=31.
Find P(B)P(B)P(B)
Find P(A∪B)P(A \cup B)P(A∪B)
Find P(B∣A′)P(B|A')P(B∣A′)
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.