please solve both problems

Question 1 The figure shows a hollow metal sphere with inner radius 4.30 cm and outer radius 12.6 cm and a point charge at the center, The inner surface of the hollow sphere has a total charge of 10.0 nC and the outer surface has a total charge of -18.6 nC. Calculate the value of the charge at the center of the metal sphere. Answer. Question 2 A charge of uniform linear density 2.31 nC/m is distributed along a long, thin, nonconducting rod, The rod is coaxial with a long conducting cylindrical shell with an inner radius of 6.55 cm and an outer radius of 11.6 cm. If the net charge on the shell is zero, what is the surface charge density on the outer surface of the shell