The successive terms of an arithmetic progression are 30, 25, 20, … .
MATHEMATICS · Multi-part · A Level · Mathematics · Sequences and series · Sequences and series
Problem
The successive terms of an arithmetic progression are 30, 25, 20, … .
(i) Find all possible values of n for which the sum of the first n terms is 75.
(ii) If only positive terms are to be included in the sum, which value of n is appropriate?