## Elementary Algebra

$t=\dfrac{A-P}{Pr}$
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}=t \\\\ t=\dfrac{A-P}{Pr} .\end{array}