| Date | May 2010 | Marks available | 2 | Reference code | 10M.2.sl.TZ1.2 |
| Level | SL only | Paper | 2 | Time zone | TZ1 |
| Command term | Find | Question number | 2 | Adapted from | N/A |
Question
Consider the arithmetic sequence 3, 9, 15, \(\ldots \) , 1353 .
Write down the common difference.
Find the number of terms in the sequence.
Find the sum of the sequence.
Markscheme
common difference is 6 A1 N1
[1 mark]
evidence of appropriate approach (M1)
e.g. \({u_n} = 1353\)
correct working A1
e.g. \(1353 = 3 + (n - 1)6\) , \(\frac{{1353 + 3}}{6}\)
\(n = 226\) A1 N2
[3 marks]
evidence of correct substitution A1
e.g. \({S_{226}} = \frac{{226(3 + 1353)}}{2}\) , \(\frac{{226}}{2}(2 \times 3 + 225 \times 6)\)
\({S_{226}} = 153228\) (accept 153000) A1 N1
[2 marks]
Examiners report
Most candidates did well on this question. Any errors were usually arithmetic in nature but candidates were able to obtain follow-through marks on errors made in earlier parts.
Most candidates did well on this question. Any errors were usually arithmetic in nature but candidates were able to obtain follow-through marks on errors made in earlier parts.
Most candidates did well on this question. Any errors were usually arithmetic in nature but candidates were able to obtain follow-through marks on errors made in earlier parts.
