You are building a large sandbox for a local playground and putting in a wooden walkway around the sandbox. The city has told you that the sandbox must be 16 feet long by 12 feet wide, and that the walkway around the sandbox must have a uniform width (call it "x"). The total area of the sandbox and the walkway combined must be 396 mm2, as that is the amount of land designated for the sandbox and walkway. What is the uniform width of the wooden walkway? How many square feet of wood do you need to build the walkway