Question 973766

The cube has volume 20*20*20=8000  micrometers^3
If I understand the problem, there is fluid put in with the equivalent of a cubic solid of 2*2*2, or 8 micrometer^3.  That would be 8/8000, 1/1000th the volume or 0.1%.

One may also do it with ratios.
it is 1 cube /another cube.
The ratio of each side is 1 to 10 or 10%
Cubing that ratio makes the total volume ratio 1 to 1000, or 0.1%