# Chapter 9 - Section 9.4 - Variation and Problem Solving - Exercise Set: 29

$r=kst^3$

#### Work Step by Step

Because $r$ varies jointly as $s$ and the cube of $t$, we equate $r$ to a constant multiple of $s$ and $t^3$: $r=kst^3$.

After 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.