Determine the sum of the first 20 terms of an arithmetic sequence in which first terms is 31 and the twentieth term is 109

CianBuckley asked Sep 22, 2023

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25 votes

Determine the sum of the first 20 terms of an arithmetic sequence in which first

terms is 31 and the twentieth term is 109

CianBuckley asked Sep 22, 2023

3.0k points

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18 votes

Answer:

1400

Explanation:

The average term is the average of the first and last terms.

average term = (31 +109)/2 = 70

The sum of the 20 term is 20 times the value of the average term:

S20 = 20(70) = 1400

Fceruti answered Sep 28, 2023

3.1k points

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