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4MA1/1F Jun 2021, Question 21: Basic Probability

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

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The question, in short

Use a biased 5-section spinner with given red, blue and green probabilities, where orange is 3 times pink, to find orange's probability and estimate blue counts in 150 spins.

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

Part (a) · 3 marks

Given red 0.20, blue 0.12, green 0.08 and orange being 3 times pink, work out the probability of landing on orange.

  1. 10.2 + 0.12 + 0.08 = 0.4
  2. 21 − 0.4 = 0.6
  3. 3Let probability of pink be x, then orange is 3x
  4. 4x + 3x = 0.6
  5. 54x = 0.6
  6. 6x = 0.15
  7. 73x = 0.45

Answer0.45

Part (b) · 2 marks

Using the spinner spun 150 times, work out an estimate for how many times it lands on blue.

  1. 10.12 × 150 = 18

Answer18

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