In a sample of college students, 40 percent are third-year students and 70 percent are not second-year students. What fraction of those students who are not third-year students are second-year students?
Let the number of students be 100.
3rd year = 40
First year or 3rd year = 70 => First year = 30
and Second year = 30
Second /First + Second = 30/60 = 1/2