Question

(\frac{r^{4}}{(3r)^{3}})

Explanation:

Step1: Expand denominator's power

$(3r)^3 = 3^3 \cdot r^3 = 27r^3$

Step2: Simplify the rational expression

$\frac{r^4}{27r^3} = \frac{1}{27} \cdot r^{4-3}$

Step3: Compute exponent difference

$r^{4-3} = r^1 = r$

Answer:

$\frac{r}{27}$