Given :   ${\mathrm{g}}_{\mathrm{m}}=\frac{{\mathrm{g}}_{\mathrm{e}}}{6}$ 
From third equation of motion
Let Initial velocity be u 
V² = u² –2g_eS₁         Final velocity
V² = u² – 2g_mS₂        V = 0 at max. height
or     $\frac{2{\mathrm{g}}_{\mathrm{e}}{\mathrm{S}}_1}{2{\mathrm{g}}_{\mathrm{m}}{\mathrm{S}}_2}=\frac{{\mathrm{u}}^2}{{\mathrm{u}}^2}=1$
or     $\frac{{\mathrm{S}}_1}{{\mathrm{S}}_2}=\frac{{\mathrm{g}}_{\mathrm{m}}}{{\mathrm{g}}_{\mathrm{e}}}=\frac{1}{6}$
or    S₂ = 6S₁ = 6 × 1.5 = 9 m