Higher June 2019 Paper 1 Q16

EdexcelHigherCurrent spec2 marksSequences

16 Here are the first five terms of an arithmetic sequence.

7 10 13 16 19

Find the sum of the first 100 terms of this sequence.

(2)

Mark scheme

Scheme	Marks
\(a = 7\) and \(d = 3\) \(\dfrac{100}{2}(2 \times 7 + (100 - 1) \times 3)\) or 100th term is 7 + (100 – 1) × 3 (= 304) and 100 × (7 + “304”) ÷ 2 or 100^th term is 3 × 100 + 4 (= 304) and 100 × (7 + “304”) ÷ 2	M1
15 550	A1
	(2)
	(2 marks)

M1: for a method to find the sum - brackets (100 – 1) must be used correctly