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0580/21 Oct/Nov 2024, Question 10: Basic Probability

Cambridge IGCSE Mathematics 0580 · Paper 21 (Extended) · Calculator · 3 marks

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The question, in short

Jacinda's game has win, lose or draw outcomes, with win probability 0.28. Find the loss probability given draw is twice as likely as loss, then the expected wins in 150 games.

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Part (a) · 2 marks

Using win probability 0.28 and draw being twice as likely as lose, work out the probability that Jacinda loses.

  1. 1P(lose or draw) = 1 − 0.28 = 0.72
  2. 2P(draw) = 2 × P(lose), so 3 × P(lose) = 0.72
  3. 3P(lose) = 0.72 ÷ 3 = 0.24

Answer0.24

Part (b) · 1 mark

Given 150 games played, find the expected number of wins using the win probability 0.28.

  1. 10.28 × 150 = 42

Answer42

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