Tyler Wallace's "Beginning and Intermediate Algebra: Section 1.10: Solving Linear Equations - Distance, Rate and Time"

Read this section. The relationship among distance, rate, and time is one of the simplest and most fundamental of physics and engineering. Notice how d = rt is a relationship that can be solved for any of the three variables.

Click https://s3.amazonaws.com/saylordotorg-resources/wwwresources/site/wp-content/uploads/2011/12/SAYLOR-MA001-TEXT.pdf link to open resource.