Answer
$30,919$
Work Step by Step
There is a constant difference, $5$, between terms.
The terms are part of an arithmetic sequence.
nth Term of an Arithmetic Sequence:
$a_{n}=a_{1}+(n-1)d$
$ 558=73+5(n-1)\qquad$... solve for n
$485=5(n-1)$
$97=(n-1)$
$n=98$
There are $98$ terms in the sum.
The terms of the sum
are the first $98$ terms of an arithmetic sequence, $a_{1}=73, d=5.$
Sum of the First $n$ Terms of an arithmetic sequence:
$S_{n}=\displaystyle \frac{n}{2}\left(a_{1}+a_{n}\right)$
$S_{98}=\displaystyle \frac{98}{2}\left(73+558\right)=49\cdot 631=30,919$
