Answer
11.88 hours
Work Step by Step
We know the equation for the period of an orbit:
$T=\sqrt{\frac{4\pi^2 r}{a}}$
We know the value of "a" is:
$a = 9.81(.058)=.5684$
We use the known values, adding the radius of the earth to the altitude, to find:
$T=\sqrt{\frac{4\pi^2 ((2+.6371)\times10^7m)}{.5684}}=42,773s=\fbox{11.88 hours}$
