Why don't YE Creationists understand that it's mathematically and biologically impossible for Noah's Arc...?

After Noahs Arc, there were apparently 8 human beings left to repopulate the entire world, 4 men and 4 women. It is impossible for 8 people to repopulate the world, it's impossible for the population to jump from 8 to 7 billion in a few thousand years.. also, how would you explain different races, Noah and his three sons were obviously not all different races, and even if they and their wives were it would take specialized inbreeding.. then each race would divide up and live in a separate part of the world.. the story is ridiculous.