[tex]\bf \qquad \qquad \textit{inverse proportional variation}\\\\
\textit{\underline{y} varies inversely with \underline{x}}\qquad \qquad y=\cfrac{k}{x}\impliedby
\begin{array}{llll}
k=constant\ of\\
\qquad variation
\end{array}\\\\
-------------------------------\\\\
\begin{cases}
y=0.2\\
x=2
\end{cases}\implies 0.2=\cfrac{k}{2}\implies 0.2\cdot 2=k\implies 0.4=k
\\\\\\
thus\qquad y=\cfrac{0.4}{x}[/tex]