In an arithmetic progression

MATHEMATICS · Multi-part · CBSE · Mathematics · Arithmetic Progressions · Arithmetic Progressions

Problem

In an arithmetic progression, the sum of the first 9 terms is three times the sum of the first 4 terms. (i) If the common difference is 2, find the first term. (ii) Hence, find the sum of the first 20 terms.

Related theory

Arithmetic Progressions
Sequences and series
Algebra
Sum of first n terms of an AP

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