If the side length of Square B is four times that of Square A, the area of Square B is how many times the area of Square A?  Choose the correct choice from the following answers
A) 20
B) 16
C) 12
D) 8
E) 4

Rationale: let x be the side length of square a . then the area of square a is x ^ 2 . the area of square b is ( 4 x ) ^ 2 = 16 x ^ 2 . the answer is b .
Answer: B