The-first-term-of-an-arithmetic-series-is-7-and-the-last-is-70-and-the-sum-is-385-find-the-number-of-terms-in-the-series-and-its-common-difference-

Question Number 192450 by Mastermind last updated on 18/May/23

The first term of an arithmetic series

is 7 and the last is 70 . and the sum is

385 . find the number of terms in the

series and its common difference .

Answered by AST last updated on 18/May/23

\frac{n (77)}{2} = 385 \Rightarrow n = 10; 7 + 9 d = 70 \Rightarrow d = 7

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