A company sends each customer an email and a text message. The events that a customer reads the two messages are modelled as independent. The probability of reading the email is 0.72, and the probability of reading neither message is 0.098.
Find the probability that a customer reads the text message.
Find the probability that exactly one message is read.
In a group of 800 customers, find the expected number who read at least one message.
Give one reason why the independence model may be unsuitable.
200 exam-style questions on OCR (MEI) A Level Maths 2.3 Probability, covering 2.3.1 Calculate the probability of an event, 2.3.2 Complementary events, 2.3.3 Expected frequency of an event, 2.3.4 Diagrams to calculate probabilities, 2.3.5 Mutually exclusive and independent events, 2.3.6 Add probabilities for mutually exclusive events, 2.3.7 Multiply probabilities for independent events, 2.3.8 Mutually exclusive and independent events (notation) (A-level only), 2.3.9 Venn diagrams for probabilities (A-level only), 2.3.10 Conditional probabilities (A-level only), and 2.3.11 Independence via conditional probability (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.