If the radius of a cylinder is doubled and so is the height, what is the new volume of the cylinder divided by the old one?	Choose the correct answer: A) 8 . B) 2 C) 6 D) 4 E) 10

Rationale: let the radius be r and the the height be h . new radius = 2 r and height = 2 h . area ( new ) : area ( old ) = pi ∗ ( 2 r ) ^ 2 ∗ 2 h / pi ∗ r ^ 2 ∗ h = 8 : 1 . hence the answer is a .
Answer: A