Which mathematical concept involves comparing two quantities of different units?

The concept of rate is fundamentally about comparing two quantities of different units, often used to express how one quantity per unit of another is changing. For example, if you are calculating speed, you might say a car travels 60 miles per hour. Here, miles and hours represent different units, and the rate effectively provides a means to relate them through a consistent measurement.

Rates are prevalent in everyday life, such as when calculating the cost of a product per unit (e.g., dollars per pound) or analyzing efficiency, like the number of words typed per minute. This comparison of differing units allows for practical applications in various scenarios, making rates essential for understanding relationships between diverse quantities.