The assembly consists of the solid rod AB, tube BC, and the lever arm. If a torque of T = 20 kip n. is applied to the rod and couple forces of P = 5 kip are applied to the lever arm, determine the required diameter for the rod, and the outer and inner diameters of the tube, if the ratio of the inner diameter d,, to outer diameter de. is required to be d/do= 0.75. The rod and the tube are made of material having an allowable shear stress of allow = 12 ksi. P 12 in. 12 in. T