Answer
$\frac{1}{6}$
Work Step by Step
(x and y are in an inverse variation if xy=k)
$\frac{1}{3}\times\frac{1}{4}=\frac{1}{12}$
so
$x\times\frac{1}{2}=\frac{1}{12}$
$\frac{1}{2}x=\frac{1}{12}$
(Multiply each side by 2)
$x=\frac{1}{6}$