Answer
$s=2A-p-230$
Work Step by Step
Using the properties of equality, in terms of $
s
$, the given equation, $
A=115+\dfrac{1}{2}(p+s)
$, is equivalent to
\begin{array}{l}
2(A)=2(115)+1(p+s)
\\\\
2A=230+p+s
\\\\
2A-230-p=s
\\\\
s=2A-p-230
.\end{array}