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0580/22 May/Jun 2025, Question 4: Basic Probability

Cambridge IGCSE Mathematics 0580 · Paper 22 (Extended) · Non-calculator · 2 marks

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The question, in short

From seven cards numbered 1 to 7, one card is chosen at random and replaced; find the probability of an odd number and the expected count in 35 repeats.

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

Part (a) · 1 mark

Find the probability that a randomly chosen card from 1 to 7 is an odd number.

  1. 1Odd numbers: 1, 3, 5, 7, which is 4 of 7 cards
  2. 2P(odd) = 4/7

Answer4/7

Part (b) · 1 mark

Using 35 repeats, calculate the expected number of times an odd card is picked.

  1. 1Expected number = 4/7 × 35 = 20

Answer20

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