Two sacks, P P\,P and QQQ, contain gold, silver, and bronze discs. Sack P P\,P contains 5 gold discs, 2 silver discs, and 1 bronze disc. Sack Q Q\,Q contains 3 gold discs, 4 silver discs, and 5 bronze discs. Alex picks one disc at random from Sack P P\,P and places it into Sack QQQ. Alex then picks one disc at random from Sack QQQ.
Draw a tree diagram to represent this information.
Find the probability that Alex picks two discs of the same colour.
Given that both discs are the same colour, find the probability they are both gold.
Practise Edexcel A Level Maths Conditional Probability with exam-style questions for A Level Maths. 100 questions covering Set Notation, Conditional Probability, Conditional Probabilities in Venn Diagrams, Probability Formulae, and Tree Diagrams, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.