Answer
$\dfrac{a^{10}}{4}$
Work Step by Step
Using the laws of exponents, the given expression, $
\dfrac{3a^{11}}{12a}
$, is equivalent to
\begin{array}{l}\require{cancel}
\dfrac{\cancel{3}a^{11-1}}{\cancel{3}\cdot4}
\\\\=
\dfrac{a^{10}}{4}
.\end{array}