Answer
Please see the work below.
Work Step by Step
We know that the escape speed is given as
$v=\sqrt{\frac{2GM}{r}}$
This simplifies to:
$r=\frac{2GM}{v^2}$
We plug in the known values to obtain:
$r=\frac{(2)(6.67\times 10^{-11})(5.97\times 10^{24})}{(30000)^2}$
$r=8.8\times 10^5m$
