Torsion in a shaft

Hi can someone tell me what is that best formula to apply to this problem?

A solid steel shaft ABCDE having diameter d = 30 mm turns freely in bearings at points A and E. The shaft is driven by a gear at C, which applies a torque T2 = 450 Nm in the direction shown. Gears at B and D are driven by the shaft and have resisting torques T1 = 275 Nm and T3 = 175 Nm, acting in the opposite direction of T2. Segments BC and CD have length LBC = 500 mm and LCD = 400 mm. Shear modulus G = 80 GPa. Determine the maximum shear stress in each part of the shaft and the angle of twist between gears B and D.
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Here's a similar solution - you can use the same method...

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