### Instruction: What is the value of the arithmetic series $28 + 30 + 32 + \cdots + 86$?### Response: I know that the sum of an arithmetic series is given by the formula $S_n = \frac{n}{2}(a_1 + a_n)$, where $n$ is the number of terms, $a_1$ is the first term, and $a_n$ is the last term.
To use this formula, I need to find $n$, $a_1$, and $a_n$.
I can see that $a_1 = 28$ and $a_n = 86$.
To find $n$, I need to figure out how many terms are in the series.
I notice that the series has a common difference of $2$, so I can use that to find $n$.
I can write $a_n = a_1 + (n - 1)d$, where $d$ is the common difference.
Plugging in the values I know, I get $86 = 28 + (n - 1)2$.
Solving for $n$, I get $n = \frac{86 - 28}{2} + 1 = 30$.
Now I have everything I need to use the formula.