If the length of the sides of two cubes are in the ratio 6:1, what is the ratio of their total surface area?  Choose the correct choice from the following:
A) 6 : 1  B) 12 : 1  C) 24 : 1  D) 36 : 1  E) 72 : 1

Rationale: "let x be the length of the small cube ' s side . the total surface area of the small cube is 6 x ^ 2 . the total surface area of the large cube is 6 ( 6 x ) ^ 2 = 216 x ^ 2 . the ratio of surface areas is 36 : 1 . the answer is d ."
Answer: D