#### Answer

$f^{-1}(x)= \frac{10^{x}}{3}$

#### Work Step by Step

We are given:
$f(x)=\log 3x$
To find the inverse, we switch $x$ and $y$ and solve for
$y$:
$y= \log 3x$
$x= \log 3y$
$10^{x}=3y$
$y=\frac{10^{x}}{3}$
Therefore:
$f^{-1}(x)= \frac{10^{x}}{3}$