Question

Select the correct answer. What is the sum of the first 17 terms of this arithmetic series? Use Sn=n(a1+an/2) .

-28 + (-13) + 2 + 17 + ⋯

A. 1,692 B. 1,564 C. 227 D. 212

Answer 1

1564.

Explanation:

First term = -28 and common difference = 15.

Sum = (17/2)(2*-28 + (17-1)15)

= 8.5 * 184

= 1564.