This document presents a probability case study involving two friends, A and B, applying for two vacancies with different probabilities of selection. The probabilities of A and B being selected are 1/4 and 1/5, respectively. The document calculates the probabilities of: (1) one of them being selected; (2) both being selected; (3) neither being selected; and (4) at least one being selected. It concludes by asking students to solve the case study on probability.