Prealgebra Lecture 6.1: Writing and Simplifying Ratios and Rates.

From a channel Lumen includes in full: Professor Leonard records his full college lectures in calculus, statistics, precalculus and differential equations; widely used as a complete free alternative to taking the class.

A 55-minute video from Professor Leonard's catalogue; the title names its topic.

Video by Professor Leonard, played through YouTube's embedded player.