The solution for the problem is:Area of the box is computed by A = 2wl + 2lh + 2hw,where w - width,the l - length, and the h - height.but we need to change that, so the formula would be:A = 2 a² + 4 a h = 300 cm²h = a (the box is a cube) A = 6 a² = 300 cm²a² = 50a = 5 cmV = a³ = 5³ = 125cm³