Given that -1 ? v ? 1, -2 ? u?  -0.5 and -2 ? z ?  -0.5 and w = vz/u, then which of the following is necessarily true?

Let A and B be two solid spheres such that the surface area of B is 300% higher than the surface area of A. The volume of A is found to be k% lower than the volume of B. The value of k must be