The densitis of two solid spheres A and B of the same radii R very with radial distance raspA(r) = k (rR) and pB (r) = k (r(R)^5, respectively, where k is a constant . The moments of inertia of the inividual spheres about axes passing through their centres are IA and IB respectively. if IB /IA = n/10, the value of n is