The load, p (in pounds), that can be safely supported by a horizontal beam varies jointly as the product of the width, w (in feet), of the beam and the square of the depth, d (in feet), and inversely as its length, l (in feet). if a beam has a width of 2 feet, a depth of 1 foot and a length of 4 feet, the load it can support is 10 pounds. how much could the beam hold if the beam had a length of 6 feet, a depth of 2 feet, and a width of 3 feet?