\(T\propto r^{3 / 2}\)
\(\frac{\mathrm{T}_{2}}{\mathrm{T}_{1}}=\left(\frac{\mathrm{r}_{2}}{\mathrm{r}_{1}}\right)^{3 / 2}=\left(\frac{\mathrm{R}+2.5 \mathrm{R}}{\mathrm{R}+6 \mathrm{R}}\right)^{3 / 2}=\frac{1}{2 \sqrt{2}} \)
\(\Rightarrow \mathrm{T}_{2}=\frac{24}{2 \sqrt{2}}=6 \sqrt{2} \mathrm{hours}\)
($R_{\text {earth }}=6400\;km$ $, r =2000\;km$ $, M _{\text {earth }}=6 \times 10^{24}\;kg$ આપેલ છે $)$