Question

Find $S_n$ for each arithmetic series described.

localid="1648546868155" $a_1=7,a_n=79,n=8$

Short answer

$S_n$for the arithmetic series is$S_8=344$ .

Step-by-step solution

Step 1. Given Information.

Given arithmetic series is $a_1=7,a_n=79,n=8$.

Step 2. Calculation.

The sum $S_n$ of the first n terms of an arithmetic series is given by

$S_n=\frac{n}{2}(a_1+a_n)$

Here, $a_1=7,a_n=79,n=8$

Plugging the values:

$\begin{array}{l}{S}_n=\frac{n}{2}(a_1+a_n)\\ S_8=\frac{8}{2}(7+79)\\ S_8=4\left(86\right)\\ S_8=344\end{array}$

Step 3. Conclusion.

Hence, the sum is $S_8=344$.