Foundation November 2021 Paper 1 Q13
13 A number sequence starts 1 2 4
Emma says that the next term is 7
(a) Explain why Emma may be correct. (1)
Here are the first four terms of the sequence of triangle numbers.
1 3 6 10
(b) Find the 8th term of this sequence. (2)
| Answer | Mark | Mark scheme |
|---|---|---|
| Explanation | C1 | for explanation Acceptable examples the sequence is going +1, +2 so the next term is +3 \(1 + 1 = 2,\ 2 + 2 = 4,\ 4 + 3 = 7\) add the current term position to the term to get the next term add the two previous terms and add 1 Not acceptable examples you add 1 each time the number goes up by 3 7 is wrong it should be 8 because you double each time |
Additional guidance
The pattern may be just seen on the sequence given
| Answer | Mark | Mark scheme |
|---|---|---|
| 36 | M1 | for finding the next term of \(10 + 5\ (= 15)\) or for \(\frac{1}{2} \times 8 \times (8 + 1)\) oe |
| A1 | cao |