Harry Potter And The Magical Sphere

Geometry Level 4

Harry Potter is playing with a Magic Sphere today, which remains as a sphere even as he changes it's physical properties. He first increases the volume of Magic Sphere by $$20\%$$.
Then he decreases the surface area by $$30\%$$.

Compute $\dfrac{\text{final radius of Magic Sphere}}{\text{original radius of Magic Sphere}} \; .$