Calculate the common difference;

Calculate the 95^th term of the sequence;

Calculate the sum of the first 250 terms.

33 = 3 + d(6)     (M1)

Note: Award (M1) for correctly substituted formula or a correct numerical expression to find the common difference.

(d =)5     (A1)     (C2)

[2 marks]

u₉₅ = 3 + 94(5)     (M1)

Note: Award (M1) for their correctly substituted formula.

= 473     (A1)(ft)     (C2)

Note: Follow through from their part (a).

[2 marks]

S₂₅₀ = 125[2(3) + 249(5)]     (M1)

Note: Award (M1) for correctly substituted formula.

S₂₅₀ = 156375     (A1)(ft)     (C2)

Note: Follow through from their part (a).

[2 marks]

Much good work was seen in parts (a) and (b) showing that many centres had well prepared their students for questions on arithmetic sequences. In part (c) however there was poor use of \({S_n} = \frac{n}{2}\){first term  + last term} with the incorrect calculation \(\frac{{250}}{2}\{ 3 + 250\} \) seen on a significant number of scripts.

Much good work was seen in parts (a) and (b) showing that many centres had well prepared their students for questions on arithmetic sequences. In part (c) however there was poor use of \({S_n} = \frac{n}{2}\){first term + last term} with the incorrect calculation \(\frac{{250}}{2}\{ 3 + 250\} \) seen on a significant number of scripts.

Much good work was seen in parts (a) and (b) showing that many centres had well prepared their students for questions on arithmetic sequences. In part (c) however there was poor use of \({S_n} = \frac{n}{2}\){first term + last term} with the incorrect calculation \(\frac{{250}}{2}\{ 3 + 250\} \) seen on a significant number of scripts.