Step 1 :Given a table of one hundred upper division students attending a career fair at a university, categorized according to class and primary career motivation.
Step 2 :We are asked to find the probability that a randomly selected student is a junior, given that their primary motivation is a sense of giving to society.
Step 3 :From the table, we can see that the number of juniors whose primary motivation is a sense of giving to society is 12.
Step 4 :The total number of students whose primary motivation is a sense of giving to society is 55.
Step 5 :The probability of an event is calculated by dividing the number of favorable outcomes by the total number of outcomes.
Step 6 :Substituting the given values into the formula, we get \( \frac{12}{55} \).
Step 7 :Final Answer: The probability that the student selected is a junior, given that their primary motivation is a sense of giving to society is \(\boxed{\frac{12}{55}}\) or approximately \(\boxed{0.218}\).