What is the exact number of 2 inch cubes that wi fit in a rectangular prim measuring 6 inches by 8 inches by 4 inches?

first, we get the volume of each solid.

for the cube, recall that volume is just
V = s^3
where s = length of a side
substituting,
V,cube = 2^3 = 8 in^3
for the rect. prism, recall that volume is just
V = l*w*h
where l = length, w = width, h = height
substituitng,
V,prism = 8*6*4 = 192 in^3
now we divide them:
192/8 = 24 cubes

hope this helps~ :)