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2.3 Probability

2.3 Probability

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Question 13

A delivery company uses three depots to distribute packages. Depot X handles 50% of the packages, Depot Y handles 30%, and Depot Z handles 20%.

If a package is handled by Depot X, the probability that it is delivered late is 4%. If a package is handled by Depot Y, the probability that it is delivered late is 5%. If a package is handled by Depot Z, the probability that it is delivered late is 10%.

a.

Draw a tree diagram to represent this information.

[3]
b.

A package is selected at random. Find the probability that it is delivered late.

[2]
c.

Given that the package is delivered late, find the probability it was handled by Depot Z.

[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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