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2.3.2 Diagrams to assist probability calculations

2.3.2 Diagrams to assist probability calculations

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Question 9

A tech support center receives inquiries through three channels: Phone, Email, and Live Chat. 45% of inquiries come through Phone, 40% through Email, and 15% through Live Chat.

The probability that an inquiry remains unresolved after the first contact is:

  • 2% for Phone
  • 3% for Email
  • 6% for Live Chat
a.

Draw a tree diagram to illustrate this situation.

[3]
b.

An inquiry is selected at random. Find the probability it is unresolved.

[2]
c.

Given that an inquiry is unresolved, find the probability it was made via the Phone channel.

[3]
Markscheme

2.3.2 Diagrams to assist probability calculations Questions

  1. A Level
  2. /Maths
  3. /2.3.2 Diagrams to assist probability calculations

26 exam-style questions on OCR A Level Maths 2.3.2 Diagrams to assist probability calculations. Each one has a worked solution and a mark scheme showing where the marks go.

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