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4024/22 May/Jun 2026, Question 8: Tree Diagrams for Independent Events

Cambridge O Level Mathematics 4024 · Paper 22 (Calculator) · Calculator · 3 marks

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The question, in short

A bag holds 7 A tiles and 5 B tiles; two tiles are drawn with replacement. Complete a tree diagram of branch probabilities and find the probability both are A.

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

Part (a) · 2 marks

Fill in the missing probability on each branch of the two-stage tree diagram for first and second tile labels.

  1. 1There are 7 + 5 = 12 tiles
  2. 2P(A) = 7/12, P(B) = 5/12
  3. 3The tile is replaced, so the second-tile probabilities are the same
  4. 4Write 7/12 on each A branch and 5/12 on each B branch

Answer7/12 on every A branch and 5/12 on every B branch

Part (b) · 1 mark

Calculate the probability that the two chosen tiles are both labelled A.

  1. 1P(A, A) = 7/12 × 7/12
  2. 2= 49/144

Answer49/144

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Also searched as: 4024/22/M/J/26 · 4024_s26_qp_22 · 4024 s26 22 · question 8.
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