Answer
$r = \frac{I}{pt}$
Work Step by Step
Our goal is to isolate r. To accomplish this we will divide both sides by pt:
I = prt
$\frac{I}{pt} = r$
$r = \frac{I}{pt}$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.