More computers at Princeton An October 2007 census revealed that 40% of Princeton students primarily used Macintosh computers (MACs). Th e rest primarily used PCs. At the time of the census, 67% of Princeton students were undergraduates.

Th e rest were graduate students. According to the census, 23% of Princeton’s graduate students said that they used PCs as their primary computers. Suppose that we select a Princeton student at random and learn that the student primarily uses a MAC. Find the probability that this person is a graduate student. Show your work.