1. The problem asks to explain Q4 in detail, specifically what the letters N, P, C, and W stand for. 2. Typically, in problems involving variables like N, P, C, and W, these letters represent quantities or parameters relevant to the context. Without the original problem statement, we can provide common interpretations: - $N$ often stands for a number or quantity, such as the number of items, population, or total count. - $P$ can represent probability, price, power, or pressure depending on the context. - $C$ usually denotes cost, concentration, capacity, or a constant. - $W$ commonly stands for weight, work, width, or wattage. 3. To give a precise explanation, please provide the original problem or context where these variables appear. 4. If Q4 is part of a specific problem, please share the problem statement so we can explain each variable accurately and solve or analyze the problem step-by-step.