Question

Mindy is taking MA 385 this Fall and two sections are offered. She estimates that if

she takes Dr. J, her chance of passing the course is 80%, but if she takes Dr. S, her
chance of passing the course is only 60%. There is a 40% chance she will get in Dr.
J's class, otherwise she will be placed in Dr. S's class. After the semester is over, you
learn that Mindy passed MA 385. What is the probability that she was enrolled in
Dr. J's section?

Answer 1

P(passed)=P(Dr. J and passed)+P(Dr. S and passed) =0.4*0.8+(1-0.4)*0.6=0.68

hence probability that she was enrolled in Dr. J's section given passed

=P(Dr. J and passed)/P(passed)=0.4x0.8/0.68=0.4706