If the length of the sides of two cubes are in the ratio 7:1, what is the ratio of their total surface area?  Choose the correct option:  A) 7 : 1  B) 14 : 1  C) 21 : 1  D) 42 : 1  E) 49 : 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 ( 7 x ) ^ 2 = 294 x ^ 2 . the ratio of surface areas is 49 : 1 . the answer is e ."
Answer: E