Answer
$r=\dfrac{7}{3}$
Work Step by Step
Adding $
-\dfrac{1}{3}
$ to both sides of the given equation, $
r+\dfrac{1}{3}=\dfrac{8}{3}
$, then,
\begin{array}{l}
r+\dfrac{1}{3}-\dfrac{1}{3}=\dfrac{8}{3}-\dfrac{1}{3}
\\\\
r=\dfrac{7}{3}
.\end{array}