Answer: 0.48
Explanation:
Let , Event A =Individuals earning more than $38,000.
Event B =Individual have a college degree
Given : The proportion of individuals in a certain city earning more than $38,000 per year :P(A)= 0.25.
The proportion of individuals earning more than $38 comma 00038,000 and having a college degree is P(A and B)= 0.12.
Using conditional probability formula , we have

i.e. Probability that an individual is a college graduate given that he is earning more than $38,000

Hence, the required probability = 0.48