we know that
[volume of a cube]=b³
where b is the length side of a cube
for b=1/3 in
Volume of a cube=(1/3)³---------> 1/27 in³
if one cube has a volume -------------> (1/27) in³
X---------------------------------------------> 1 in³ (volume of a prism)
X=1/(1/27)---------> 27 cubes
the answer is 27 cubes