Since you are trying to find time, represented by t, you set the equation equal to t. Then you need to add n multiplied by miles, m, to the fixed rate, r.
The increase of volume = volume of the cube = 1 cubic foot = 1728 cu ins Area of the base = 12 sq ft = 12 * 144 = 1728 sq ins The height of increase = 1728 / 1728 = 1 inch Answer
