if kinetic energy is increased by 300% then change in momentum is increased by

As

Kinetic energy, KE = (1/2)*m*v²

Linear momentum, P = m v

if kinetic energy of the body is increase by 300% then

New KE becomes 4 times  (1/2)*m*v²and

 can be given as  (1/2)*m*(2v)²since

 other factors will not change being constants.

∴ New Linear momentum becomes 2 (m v) i.e. increased by 100% .

Hope it helps!