In a large group of employees, the probability that an employee has a company phone (PPP) is 0.45, the probability that they have a company laptop (LLL) is 0.60, and the probability they have both is 0.30.
Find the probability that a randomly chosen employee has a company phone or a company laptop, P(P∪L)P(P \cup L)P(P∪L).
Given that a randomly chosen employee has a company laptop, find the probability they also have a company phone, P(P∣L)P(P|L)P(P∣L).
Find the probability that a randomly chosen employee does not have a company phone, given that they do not have a company laptop, P(P′∣L′)P(P'|L')P(P′∣L′).
200 exam-style questions on OCR A Level Maths 2.3 Probability, covering 2.3.1 Mutually exclusive and independent events, 2.3.2 Diagrams to assist probability calculations, 2.3.3 Conditional probability (A-level only), 2.3.4 Conditional probability from first principles (A-level only), and 2.3.5 Modelling with probability. Each one has a worked solution and a mark scheme showing where the marks go.