Tyco

The sun is a satellite of Milky Way's galactic central cluster. The sun revolves around this center with a radius of 2.28x10^20 m. and with a period of 2.52x10^8 years. If the universe is 16 billion years old. a) How many times has the galaxy rotated and...

Can someone please teach me how to get to the correct solution. I've been on this question for sometime already, still I haven't figure it out.