Foundation June 2023 Paper 1R Q5
5 Here are the first four terms of a number sequence.
2 6 10 14
Elsie correctly works out that the next term in the sequence is 18
(a) Explain how she was able to work this out. (1)
(b) Explain why 217 cannot be a number in the sequence. (1)
| Scheme | Marks |
|---|---|
| Correct explanation | B1 |
| (1) |
Notes
B1: eg ‘she added 4’, ‘add 4’, +4, rule is \(4n - 2\), goes up by 4, \(4 \times 5 - 2\) (= 18)
| Scheme | Marks |
|---|---|
| Acceptable answers 1. (the) sequence is even 2. (217) is odd or not even 3. ‘\(n\)th term is \(4n - 2\) which will always be even’ 4. ‘sequence goes 214, 218’ 5. (the) 54th term is 214 6. it would be 218 (not 217) 7. \(4n - 2\) so \(n\) is not an integer/whole number 8. 219 ÷ 4 oe (= 54.75) not an integer/whole number 9. not 2 less than a multiple of 4 10. does not end with 0, 2, 4, 6 and 8 (must have all 5 numbers) 11. each digit has an even digit at the end/does not end in an even number Not acceptable answers 1. adding 4 each time will not lead to 217 2. it goes past 217 3. 217 ÷ 4 (= 54.25) not an integer/whole number Answer: Correct explanation | B1 |
| (1) | |
| (2 marks) |