Foundation November 2022 Paper 1 Q12
12 Here are the first four terms of a sequence.
\[7 \qquad 15 \qquad 23 \qquad 31\](a) Write down the next term of the sequence. [1]
(b) Explain how you worked out your answer. [1]
(c) Explain why 80 is not a term in this sequence. [1]
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| 39 | 1 | Ignore extras after 39 | |
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| Add 8 | 1 | Need direction and quantity | |
| Answer | Marks | Part marks and guidance | |
|---|---|---|---|
| The sequence is all odd numbers oe | 1 | See appendix | |
Appendix
Exemplar responses for 12c
| Response | Mark |
|---|---|
| \(8n - 1 = 80\) ; \(n = 10.125\) it’s not an integer | 1 |
| The last digits of the number always end with 1, 3, 5, 7, 9 never 0 | 1 |
| After 79 it goes to 87 | 1 |
| After 71 it goes to 79 so 80 can’t be | 1 bod |
| If you add on in 8’s you get to 79 not 80 | 1 bod |
| Nearest term would be 79 which is 1 off | 1 bod |
| …. 39, 47, 55, 63, 71, 79, 87 | 1 bod |
| \(80 \div 8 = 10\) | 0 |
| There is 79 in the sequence, followed by the sequence to 79 | 0 |
| Because the sequence didn’t start at 0 it started at -1 mean that the sequence isn’t the 8 times table | 0 |
| Because the next two terms only take you to 79 | 0 |
| Because each term is prime | 0 |
| None of the terms end in 0 / are a multiple of 10. | 0 |
| Because 80 is an even number – not enough | 0 |
| Because it’s not possible to add 8 from the terms to get to 80 | 0 |