The first term of an arithmetic progression is and its 20th (last) term is

MATHEMATICS · Single correct · A Level · Mathematics · Sequences and series · Sequences and series

Problem

The first term of an arithmetic progression is

4

and its 20th (last) term is

99

. What is the sum of these 20 terms? (a)

1080

(b)

1030

(c)

979

(d)

2060