Higher November 2023 Paper 2 Q29
29 A code is three letters, each of which is in the word \(\quad\) LOGIC
Vinny assumes that letters in the code may be used more than once.
He works out how many possible codes there are.
In fact, the first two letters are the same and the third is different.
How many of Vinny’s codes are not possible? [2 marks]
| Answer | Mark | Comments |
|---|---|---|
| Alternative method 1 | ||
| \(5 \times 5 \times 5\) or 125 or \(5\,(\times 1) \times 4\) or 20 | M1 | oe |
| 105 | A1 | |
| Alternative method 2 | ||
| \(5\,(\times 1 \times 1)\) or 5 and \(5 \times 4\,(\times 1)\) or 20 and \(5 \times 4 \times 3\) or 60 | M1 | oe \(5 \times 4\,(\times 1)\) or 20 may appear twice |
| 105 | A1 | |
Additional guidance
| The first M1 may be awarded for correct work with no answer or incorrect answer, even if this is seen amongst multiple attempts | |
| \(5 \times 4\,(\times 1)\) or 20 | M1 |