Question 10 - A-Level Maths

Exam Board	AQA
Module	Paper 1 (Paper 1)
Year	2020
Session	June
Marks	4
Topic	Arithmetic Sequences and Series

An arithmetic series is given by $$\sum _ { r = 5 } ^ { 20 } ( 4 r + 1 )$$ 10
1. Write down the first term of the series.
  10
(ii) Write down the common difference of the series.
10
(iii) Find the number of terms of the series.

10
A different arithmetic series is given by $\sum _ { r = 10 } ^ { 100 } ( b r + c )$
where $b$ and $c$ are constants.
The sum of this series is 7735
10
(ii) The 40th term of the series is 4 times the 2nd term. Find the values of $b$ and $c$.
[0pt] [4 marks]