An aluminum tube of 3-in. outside diameter is to carry a load P of 10 kips having an eccentricity e = 0.6 in. Knowing that the stock of tubes available for use are made of aluminum alloy 2014-T6 and have wall thicknesses in increments of in. up to in., determine the lightest tube that can be used. Use the interaction method of design with an allowable stress in bending of 25 ksi. (Input the final answer as a fraction.) e = 0.6 in.- A 3-in, outside diameter 6 ft The lightest tube that can be used should have a wall thickness of ( ) in.