Write down the common difference.

Find the number of terms in the sequence.

Find the sum of the sequence.

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]

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.