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A-LevelMathematicsProbability and statistics9709/63 · Oct/Nov 2019 · Q25 Marks

How many different arrangements are there of the 9 letters in the word CORRIDORS?

  1. (i)How many different arrangements are there of the 9 letters in the word CORRIDORS?[2]
  2. (ii)How many different arrangements are there of the 9 letters in the word CORRIDORS in which the first letter is D and the last letter is R or O?[3]

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2019). The mark or mark type is shown in brackets.

  1. [B1] 9! Divided by at least one of 2! or 3!
  2. [B1] Exact value
  3. [B1] 7! Seen alone or as numerator in a term, can be multiplied not + or
  4. [B1] One term correct, unsimplified
  5. [B1] Final answer

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About this question

Topic
Probability and statistics, A-Level Mathematics (syllabus 9709). Structured question, 5 marks.
Source
A-Level Mathematics, Oct/Nov 2019 Paper 6 Variant 3, question 2.

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