ve and vp denotes the escape velocity from the earth and another planet having twice the radius and the same mean density as the earth. Then
ve=vp
ve=vp/2
ve=2vp
ve=vp/4
ve=2GMR=R83πGρ
If mean density is constant, then ve∝R
vevp=ReRp=12 ⇒ ve=vp2