Answer:
10 seconds
Explanation:
If the height is modeled by the function [tex]h(t)=-15t^{2} +150t[/tex], then the seconds it takes to reach the water (when the height equals 0) is modeled by the following.
[tex]0=-15t^{2} +150t\\0=-15t*(t-10)\\\\t=0\\t=10[/tex]