11. MINIMIZING PACKAGING COSTS A rectangular box is to have a square base and a volume of 20 ft. If the material for the base costs 30/ft2, the material for the sides costs 10/ft, and the material for the top costs 20/ft2, determine the dimensions of the box that can be constructed at mini- mum cost. (Refer to the figure for Exercise 10.)

11. Minimizing Packaging Costs A rectangular box is to have a square base and a volume of 20ft3. If the material for the base costs 30//ft2, the material for the sides costs 10//ft2, and the material for the top costs 20%/ft2, determine the dimensions of the box that can be constructed at minimum cost. (Refer to the figure for Exercise 10.)