Solution: Soup Servings

Statement

You begin with two types of soup, A and B, each containing n milliliters. During each turn, exactly one of the following four operations is selected uniformly at random (each with probability $0.25$), independent of all prior turns:

• Serve $100$ mL of soup A and $0$ mL of soup B.

• Serve $75$ mL of soup A and $25$ mL of soup B.

• Serve ...