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2.3 Probability

2.3 Probability

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Question 54

A company has three machines that produce a component. Machine A produces 40% of the components. Machine B produces 35% of the components and machine C produces 25% of the components.

If a component is produced by machine A the chance that it will be faulty is 3%. If a component is produced by machine B the chance that it will be faulty is 2%. If a component is produced by machine C the chance that it will be faulty is 1%.

a.

Draw a tree diagram to show this information.

[3]
b.

A component is selected at random. Find the probability it is faulty.

[2]
c.

Given that the component is faulty, find the probability it was produced by machine C.

[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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