As a current PhD student, I have to tell you that it doesn’t work that way. PhD’s aren’t awarded after going to school for x number of years. There’s really no way to know for sure, but I’d imagine she went four years for undergrad and then four or five years for graduate school, depending on how long it took her to pass her qualifying exams (if she had them) and how long it took her to write her dissertation. But don’t think of it in terms of years because the degree is awarded once you are good enough to make an original contribution to the field…..she could’ve done that after two years if she was exceptional, and that would be truly impressive indeed.