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4MA1/1H Jan 2021, Question 14: Tree Diagrams for Dependent Events

Pearson Edexcel International GCSE Mathematics A 4MA1 · Paper 1H (Higher) · Calculator · 5 marks

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The question, in short

Using the probability tree for Ding's two snooker games against Marco and Judd, find the chance he wins both games, and the chance he wins exactly one.

Summarised in our own words. Use the official paper for the exact wording and the diagram.

Part (a) · 2 marks

Calculate the probability that Ding wins both games, using the branch probabilities for beating Marco then Judd.

  1. 1Win both = win against Marco, then win against Judd.
  2. 2Multiply along the branches: 0.6 × 0.9 = 0.54

Answer0.54

Part (b) · 3 marks

Calculate the probability that Ding wins exactly one of the two games, combining the relevant outcomes.

  1. 10.6 × 0.1 = 0.06
  2. 20.4 × 0.25 = 0.1
  3. 30.06 + 0.1 = 0.16

Answer0.16

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