Question $22$

If $f(x)=5\frac{x}{20},$ what is the equation for generating $x,$ given the random number $r?$

$x=r\sqrt[\phantom{2}]{8}$

$x=4\sqrt[\phantom{2}]{r}$

$x=2\sqrt[\phantom{2}]{2r}$

$x=\sqrt[\phantom{2}]{\frac{5r}{20}}$

None of the above