A steel tube of 80-mm outer diameter is to carry a 165-kN load P with an eccentricity of 15 mm. The tubes available for use are made with wall thicknesses in increments of 3 mm from 6 mm to 15 mm. Using the interaction method and an allowable stress in bending of 150 MPa, determine the lightest tube that can be used. Assume E=200 GPa and y= 250 MPa. e=15 mm 2.2 m 80-mm outer diameter The lightest tube that can be used should have a thickness of mm.