Passing stats Molly’s university offers two sections of Statistics 101.

From what she has heard about the two professors listed, Molly estimates that her chances of passing the course are 0.80 if she gets Professor Scedastic and 0.60 if she gets Professor Kurtosis. The registrar uses a lottery to randomly assign the 120 enrolled students based on the number of available seats in each class. There are 70 seats in Professor Scedastic’s class and 50 in Professor Kurtosis’s class.

a) What’s the probability that Molly will pass Statistics?

b) At the end of the semester, we find out that Molly failed. What’s the probability that she had Professor Kurtosis?