I am talking calc 2 and i found this example in the book in the practice examples its question 12 in the book chapter 6.4. I tried to solve it but I did not get the Idea

please explain the solution

Dinosaur fossils are too old to be reliably dated using carbon-14. (SeeExercise 11.) Suppose we had a-million-year-olddinosaur fossil. What fraction of the living dinosaur'swould be remaining today? Suppose the minimum detectable amount is. What is the maximum age of a fossil that we could date using?