Explanation:
\(V = \frac{{ - GM}}{{R + h}} = - 5.4 \times {10^7}{\mkern 1mu} {\mkern 1mu} \,\,\,\,\,\,\,\,(1)\)
and \(g = \frac{{GM}}{{{{(R + h)}^2}}} = 6\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,(2)\)
dividing (1) and (2)
\(\Rightarrow \dfrac{5.4 \times 10^{7}}{(R+h)}=6\)
\( \Rightarrow R + h = 9000\;km\) so \(h = 2600\;km\)