A bag contains k k\,k blue counters, 8 red counters and 6 green counters. Two counters are removed from the bag at random, where k k\,k is a positive integer.
Draw a tree diagram to represent this information
Find, in terms of kkk, the probability that the two counters removed are both green
Given that at least one of the counters removed is red, find, in terms of kkk, the probability that both counters are red.
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.