Here's a problem I came across:
In a bag, there are $30$ one-color marbles of three different colors, say black, blue, and white. If we randomly take $25$ marbles out of the bag, among our picks will always be at least three white, at least five blue, and at least seven black marbles. How many marbles of each color are there in the bag originally?
From my interpretation of the wording, every sample of $25$ will have at least $3$ white, $5$ blue, and at least $7$ black. What's the most concise way to answer the question with my interpretation of the situation?