If two resistors with resistances $R_1$ and $R_2$ are connected in parallel, as in the figure, then the total resistance $R$, measured in Ohms $(\Omega)$, is given by: $$\displaystyle\frac{1}{R} =\frac{1}{R_1}+\frac{1}{R_2}$$
If $R_1$ and $R_2$ are increasing at rates of $.3\,\Omega/s$ and $.2\, \Omega/s$, respectively, how fast is $R$ increasing when $R_1=80\,\Omega$ and $R_2=100\,\Omega$?

$\Omega/s$