Coaxial cable consists of a 2.0mm diameter inner conductor and outer conducter w

Coaxial cable consists of a 2.0mm diameter inner conductor and outer conducter with interior diameter 1.0 cm .?
A 100 mA current flows down the inner conductor .The thickness of the walls of the outer conductor is 5.0 mm.A 200 mA current flows back along the outer conductor .Find the magnetic field strength a.0.50mm b.5.0 mm c.1.2cm d.2.0cm from the cable axis