In a university, there are two statistics tutors named Susan and David. The student's final exam marks were recorded, and it was found that out of a total of 250 students, 150 were in tutorials run by Susan, while the rest were in tutorials run by David.

Out of Susan's students, 120 passed the final exam; while out of David's students, 90 passed. If one randomly selected student passed the final exam, find the probability that the student was in a tutorial run by David.