Answer:
t > 3.66667 minutes
Step-by-step explanation:
The height of the hiker at any time is given by
H(t) = -50 + 15t
At H = 5 ft,
5 = -50 + 15t
15t = 55
t = (11/3) = 3.6667 minutes; the hiker's elevation is exactly 5 ft at this point.
From then on,
H(t) > 5 ft
-50 + 15t > 5
t > 3.6667 minutes