Answer:
t = 56.6 s
Explanation:
In the absence of air resistance we can use the kinematic equation
s = ½at²
The package is at vertical rest at the drop point. The horizontal velocity will not matter.
t = √(2s/a)
t = √(2(15721)/9.81)
t = 56.6 s
With air resistance, the time will likely be significantly longer as terminal velocity probably has been achieved.
Without air resistance, the velocity at ground impact would be
v = at = 9.81(56.6) = 555 m/s
which is almost double the speed of sound in air, so air resistance is not negligible.
