A compound thin cylinder comprising two concentric thin cylinders has a common diameter of 100 mm. The inner cylinder has a thickness of 2.5 mm. The radial pressure between the two cylinders is 200 kPa, and the difference between the common diameters of the two cylinders before shrinkage was 4.305x10^-3 mm. If the compound cylinder is subjected to an internal pressure of 180 kPa, and the elastic modulus for the material for both cylinders is 200 GPa, determine the thickness of the outer cylinder and the resultant hoop (circumferential) stresses in both cylinders.