The volume of the rectangular prism is length x width x height:
Volume = 1 1/2 x 1/2 x 3/4 = 9/16 cubic units.
The volume of cube is length^3 = 1/4^3 = 1/64
Divide the volume of the rectangular prism by the volume of the cube:
Number of cubes = 9/16 / 1/64 = 36
The answer is 36