Answer
See below
Work Step by Step
Given: $y_0=5$ ft
$v_0=30$ ft/sec
The position of the ball is $y=y_0+v_0t-16t^2$
Set $y=0$,
$16t^2-30t-5=0\\
\rightarrow t=\frac{15 \pm \sqrt 305}{16}$
We will take only positive values: $t \approx 2029$