If the mass of a body is doubled, its kinetic also gets doubled and if the mass of a body is halved, its kinetic energy also gets halved.

If the velocity of a body is doubled, its kinetic energy becomes four times and if the velocity of a body is halved, then its kinetic energy becomes one- fourth.

It is obvious that doubling the velocity has a greater effect on the kinetic energy of a body than doubling its mass.