The partial sum of an arithmetic sequence is 1070

MATHEMATICS · Subjective · CBSE · Mathematics · Arithmetic Progressions · Arithmetic Progressions

Problem

The

20^{\text {th }}

partial sum of an arithmetic sequence is 1070 . The sum of its fifth term and its tenth term is 65 . a. Write an expression for the

\mathrm{n}^{\text {th }}

term of this sequence. b. Find the

30^{\text {th }}

partial sum of this sequence.