The table below shows the membership type of each of 200 customers and whether the customer uses a mobile app.
| Uses the app | Does not use the app | Total | |
|---|---|---|---|
| Basic | 68 | 12 | 80 |
| Premium | 42 | 78 | 120 |
| Total | 110 | 90 | 200 |
One customer is selected at random. The event B B\,B is that the customer has basic membership, and the event U U\,U is that the customer uses the app.
Find P(B∩U)P(B \cap U)P(B∩U).
Find P(B∪U)P(B \cup U)P(B∪U).
Find P(B′∩U′)P(B' \cap U')P(B′∩U′).
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.