A solid sphere of radius R is concentric with a conducting spherical shell that carries charge +qshell and has an inner radius of 2R and an outer radius of 3R. If the electrostatic potential at the common center of the sphere and shell is the same as the potential at infinity, what is the charge q sphere on the solid sphere if a.) the sphere is conducting and b.) the sphere is nonconducting and has a uniform charge distribution throughout it?