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2.3 Probability

2.3 Probability

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Question 36

A mobile game is available on three platforms. 60% of downloads are from the App Store, 25% from the Play Store, and 15% from a Web Download.

The probability that a download from the App Store results in a bug report is 1%. The probability that a download from the Play Store results in a bug report is 2%. The probability that a download from a Web Download results in a bug report is 6%.

a.

Draw a tree diagram to show this information.

[3]
b.

A download is selected at random. Find the probability it results in a bug report.

[2]
c.

Given that a download resulted in a bug report, find the probability it was from the Play Store.

[3]
Markscheme

2.3 Probability Questions

  1. A Level
  2. /Maths
  3. /2.3 Probability

200 exam-style questions on OCR A Level Maths 2.3 Probability, covering 2.3.1 Mutually exclusive and independent events, 2.3.2 Diagrams to assist probability calculations, 2.3.3 Conditional probability (A-level only), 2.3.4 Conditional probability from first principles (A-level only), and 2.3.5 Modelling with probability. Each one has a worked solution and a mark scheme showing where the marks go.

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