Question 1133275
The equation's "24" is the height above the water.  Solve this for h=0, water level
-16t^2+20t+24=0
-4t^2+5t+6=0 or 4t^2-5t-6=0
(4t+3)(t-2)=0
t=2 only positive root.
2 seconds ANSWER
{{{graph(300,300,-5,5,-20,60,-16x^2+20x+24)}}}