If the radius of a sphere is doubled, how many times does its volume become?

Question: If the radius of a sphere is doubled, how many times does its volume become?

Solution:
Let the original radius be r.
Then, original volume = (4/3)πr³

New radius = 2r
∴ New violume = (4/3)π(2r)³
= 8 × (4/3)πr³
= 8 × original volume