Twenty percent of students in a college ever go to their professor during office hours. Of those

Question:

Twenty percent of students in a college ever go to their professor during office hours. Of those who go, 30% seek minor clarification and 70% seek major clarification.
a. What is the probability that a student goes to the professor during her office hours for a minor clarification?
b. What is the probability that a student goes to the professor during her office hours for a major clarification?