Answer
$t=\dfrac{A-p}{pr}$
Work Step by Step
Using the properties of equality, in terms of $
t
,$ the given equation, $
A=p+prt
,$ is equivalent to
\begin{array}{l}\require{cancel}
A-p=prt
\\\\
\dfrac{A-p}{pr}=\dfrac{prt}{{pr}}
\\\\
\dfrac{A-p}{pr}=t
\\\\
t=\dfrac{A-p}{pr}
.\end{array}