Final answer:
It will take 0 seconds to be 250 feet above the water for the given function.
Step-by-step explanation:
To find out how long it will take to be 250 feet above the water for the function f(t) = -4t² + 250, we need to find the value of t when f(t) = 250.
So we set -4t² + 250 = 250 and solve for t:
-4t² = 0
t² = 0
t = 0
Therefore, it will take 0 seconds to be 250 feet above the water for the given function.