\(\frac{V_P}{V_E}=\frac{\sqrt{\frac{2 G_P}{R_p}}}{\sqrt{\frac{2 G_E}{R_E}}}=\sqrt{\frac{R_E}{R_P} \times \frac{M_P}{M_E}}\)
\(V_P=\sqrt{\frac{1}{4} \times 9} \times V_E=\frac{3}{2} V_E\)
\(V _{ P }=\frac{3}{2} \times 11.2\,km / sec\)
\(=16.8\,km / sec\)