Final answer:
The subject of this question is Mathematics. The given information describes a situation in a factory where the number of workers is constant and provides examples of the relationship between the time taken to make a unit and the number of units made per day.
Step-by-step explanation:
The subject of this question is Mathematics. The given information describes a situation in a factory where the number of workers is constant. It provides examples of the relationship between the number of minutes it takes to make a single unit of a product (n) and the number of units of the product that are made per day (u). For instance, if 40 workers in the United States are making shoes and it takes four workers to make 1,000 shoes, then a total of 10,000 shoes will be produced.