A right rectangle prism has a length of 2 1/2 feet, a width of 3 feet, and a height of 1 1/2 feet. Unit cubes with side lengths
of 1/2 foot are added to completely fill the prism with no space remaining. What is the volume, in cubic feet, of the right rectangular prism? How many 1/2 foot unit cubes can be added to fill the prism completely?