I am studying chemistry, and I am supposed to answer this question, which isn't explained how to solve in its book. I thought you'd might have some experience, so if you do, please explain for me how this is to be solved:
"The relative atomic mass of iridium is 192.2. Iridium occurs naturally as a mixture of iridium-191 and iridium-193. What is the percentage of each isotope in naturally-occuring iridium?"