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

85.5

92.5

90.5

87.5

Correct Answer : D

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?