A bag contains 10 blue counters, 8 red counters and 6 green counters. Two counters are removed at random, without replacement.
Find the probability that both counters are red.
Find the probability that the two counters are different colours.
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.