A bag contains b b\,b blue counters, 8 red counters and g g\,g green counters, where b>gb>gb>g. Two counters are removed from the bag at random.
Given that the probability that the two counters removed are both red is 769\displaystyle \frac{7}{69}697, find b+gb+gb+g.
Given that the probability that the two counters removed are different colours is 4769\displaystyle \frac{47}{69}6947, find b b\,b and ggg.
186 exam-style questions on Edexcel A Level Maths Probability, covering 5.1 Calculating Probabilities, 5.2 Venn Diagrams, 5.3 Mutually Exclusive and Independent Events, and 5.4 Tree Diagrams. Each one has a worked solution and a mark scheme showing where the marks go.