Probability Theory
After a grueling nationwide examination, it was announced that
70% of students passed the Mathematics examination, and
60% of students passes the Science examination.
What is the minimum percentage of students that passed both examinations?
In a class of students, of the students passed the physics exam and of the students passed the math exam.
What is the minimum percentage of students in the class that passed both exams?
How many numbers in the set are divisible by or
A party of vile creatures is marching through the woods. Each of the creatures is either an orc, a goblin, or a half-orc/half-goblin. If there are creatures that are at least partly goblin, and creatures that are at least partly orcs, how many of the creatures are half-orc/half-goblins?
Consider all -digit positive numbers using all of the digits . How many of these numbers have even first or second digit?