Sampling without replacement tree diagram

Questions involving drawing items from a container without replacement, where probabilities change based on what was previously drawn.

1 questions · Easy -1.2

2.03b Probability diagrams: tree, Venn, sample space
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Edexcel S1 2006 January Q4
7 marks Easy -1.2
4. 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.
  1. Draw a tree diagram to represent the information. Find the probability that
    1. the second ball selected is red,
    2. both balls selected are red, given that the second ball selected is red.