A bag contains 9 blue balls and 3 red balls. A ball is selected at random from the bag and its colour is recorded. The ball is not replaced. A second ball is selected at random and its colour is recorded.
Draw a tree diagram to represent the information.
Find the probability that the second ball selected is red.
Find the probability that both balls selected are red, given that the second ball selected is red.
Practise Edexcel A Level Old Maths Probability with exam-style questions for A Level Old Maths. 11 questions, matched to the Edexcel A Level Old Maths (9371) specification and written in Unit exams C1, C2, C3 and C4 plus two applied units (e.g. S1 and M1) 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.