Of 62 students, 32 are freshmen, 32 are economic majors, and 12 are neither.
Subtract 12 from 62, giving 50 students who are either freshmen, economic majors or both.
If being a freshman is independent from being an economic major, adding the number of fresmen to the number of economic majors could, at most, be 50 students.
However, when you add 32 freshmen to the 32 economic majors, you get a total of 64 students. This means that 14 students must be both freshmen and economic majors (you get 14 by subtracting 50 from 64).
The probability that a student, drawn at random, is both an economics major and a freshman is:
14 / 62 = 7/31.