A steel shaft ABCD having a total length of 3 m consists of the following different sections:
AB is hollow having outside and inside diameters of 10 cm and 6.25 cm, respectively, and BC and CD are solid, BC having a diameter of 10 cm and CD a diameter of 8.75 cm. Find the safe applied torque that can be transmitted by the shaft ABCD, if the maximum shear stress in the hollow section is 47 MPa and G = 82.5 GPa. If the angle of twist is the same for each portion, determine the length of each section.