? How small would a black hole be if it had the mass of the Sun? How much bigger would the black hole be if it had, say, 10 times the mass of the Sun?...

1. Do black holes actually exist in the universe? How small would a black hole be if it had the mass of the Sun? How much bigger would the black hole be if it had, say, 10 times the mass of the Sun? Or, 1 million times the mass of the Sun? What observations have been made that demonstrate that black holes exist?
2. As the Universe homogeneously filled with galaxies? If not, what is the pattern of filled and unfilled regions? How is Hubble's Law relating a galaxy's velocity to its distance used "backwards" to find the distances to enough galaxies to reveal that pattern of filled and unfilled regions?

If you know either or both that would be great. These are from an exam review sheet. Also if I could get a response by tonight or 8am tomorrow at the latest that would be incredible.