1MA0 Foundation November 2012 Paper 1 Q12
12 Here are the first four terms of a number sequence.
3 7 11 15
(a)
(i) Write down the next term in the sequence.
(ii) Explain how you got your answer. (2)
(b) Work out the difference between the 10th term and the 15th term in the sequence. (2)
| Answer | Mark | Notes |
|---|---|---|
| (i) 19 (ii) Add 4 | 2 | (i) B1 cao (ii) B1 for add 4 (+4) oe or \(4n - 1\) (or \(\times 4 - 1\)) |
| Working | Answer | Mark | Notes |
|---|---|---|---|
| \(15 - 10 = 5\) \(5 \times 4 = 20\) | 20 | 2 | M1 for \((15 - 10) \times 4\) or \(4 + 4 + 4 + 4 + 4\) or 59, 39 or \((4 \times 15 - 1) - (4 \times 10 - 1)\) or ‘59’ − ‘39’ from a list A1 cao |