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4MA1/1H Jan 2022, Question 14: Tree Diagrams for Independent Events

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

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The question, in short

Aika picks one seed at random from packet A (12 seeds, 7 sunflower) and one from packet B (15 seeds, 8 sunflower). Complete a probability tree and find the chance both are sunflower.

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

Part (a) · 2 marks

Fill in the missing probabilities on the tree diagram for packet A and packet B branches, including sunflower and not sunflower outcomes.

  1. 1Packet A, not sunflower: 1 − 7/12 = 5/12
  2. 2Packet B, sunflower: 8/15; not sunflower: 1 − 8/15 = 7/15
  3. 3Both pairs of packet B branches are the same: 5/12, 8/15, 7/15, 8/15, 7/15

Answer5/12, 8/15, 7/15, 8/15, 7/15

Part (b) · 2 marks

Work out the probability that the two seeds Aika takes are both sunflower seeds.

  1. 17/12 × 8/15
  2. 256/180
  3. 3simplify 56/180 by dividing numerator and denominator by 4
  4. 414/45

Answer14/45

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