the ball was dropped from 150 feet
as to solve it- plus 0 in for h(t)
0=-16t^2+150
now from here there are many ways to solve for t... this is how i'd be doing it-
0=-8t^2+75
-75=-8t^2
9.375=t^2
-3.06, 3.06=t
but since you know that the answer has to be positve, the answer is 3.06 seconds