Arectangular prism is completely packed with 54 cubes of edge length fraction 1 over 2 inch, without any gap or overlap. which of these best describes the volume of this rectangular prism? 6 unit cubes and 6 smaller cubes of volume fraction 1 over 8 cubic inch each 13 unit cubes and 4 smaller cubes of volume fraction 1 over 8 cubic inch each 6 unit cubes and 3 smaller cubes of volume fraction 1 over 8 cubic inch each 13 unit cubes and 2 smaller cubes of volume fraction 1 over 8 cubic inch each