Grade 12 Maths · Probability

Use the counting principle

Count arrangements by multiplying the choices for each position, for example a 4-digit PIN has 10 × 10 × 10 × 10 = 10 000 options.

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The Counting PrincipleMindset
Probability: Lesson: The Fundamental Counting PrincipleMindset
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Question 12.1 · November 2024 · Paper 1 · National (DBE) · 2 marks

A company generates a 4-character code using the 26 letters of the alphabet and the 10 digits, from 0 to 9. The code is in the form: Letter Digit Letter Digit.Diagram for this question
12.1 Determine how many different codes can be formed if letters and digits may be repeated.(2)

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  1. 3. Question 11.3.2 · May/June 2024 · Paper 1 · National (DBE) · 3 marks

    11.3 Seven guitar players, each with a different name, participate in a concert.
    11.3.2 After the performance, the guitar players wait backstage. There is a bench with only room for four to sit on. What will be the probability that the four guitar players will be sitting in alphabetical order, from left to right?(3)
    Show the memo (2 ticks)
    1. ✓
      Calculate total sample space for arranging 4 from 7

      2 marks · Use the counting principle

    2. ✓
      Calculate probability for the single successful arrangement

      1 mark · Calculate a simple probability

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