This is the way I tried to solve this.
X = The number of students that pass out of 25 students present last class.
Y = The number of students that pass out of 5 students absent last class.
T = Total number of students pass out of 30 students.
X~Bin(25,0.85) and Y~Bin(5,0.20)
(Moderator's note: thread moved from "Set Theory, Logic, Probability, Statistics ")
"A lecturer gives spot quizzes in randomly selected classes. In those quizzes he asks questions from the material covered in the previous class. From experience it is known that a student has 0.85 chance of...