Answer
$-\dfrac{4(5+4y)}{3y}$
Work Step by Step
The given expression, $
\dfrac{\dfrac{1}{y}+\dfrac{4}{5}}{-\dfrac{3}{20}}
,$ simplifies to
\begin{array}{l}\require{cancel}
\dfrac{\dfrac{5(1)+y(4)}{5y}}{-\dfrac{3}{20}}
\\\\=
\dfrac{\dfrac{5+4y}{5y}}{-\dfrac{3}{20}}
\\\\=
\dfrac{5+4y}{5y}\div\left( -\dfrac{3}{20} \right)
\\\\=
\dfrac{5+4y}{5y}\cdot\left( -\dfrac{20}{3} \right)
\\\\=
\dfrac{5+4y}{\cancel{5}y}\cdot\left( -\dfrac{\cancel{5}\cdot4}{3} \right)
\\\\=
-\dfrac{4(5+4y)}{3y}
.\end{array}
