Final answer:
The questions involve calculating various probabilities, including simple, joint, conditional, and those involving probability distribution functions, which is a high school-level topic in Mathematics.
Step-by-step explanation:
The subject of these questions is Mathematics, and they pertain to probability, which falls under the category of statistics within mathematics. The questions present a variety of scenarios involving probability calculations. These include calculating simple probabilities, joint and conditional probabilities, independent and mutually exclusive events, and working with probability distribution functions (PDFs). The grade level for these types of questions is typically high school, where students are introduced to the fundamental concepts of probability.