Lesson · M.1.9
Ratios and rates of change
The difference between a ratio and a rate, how to reduce either to a unit rate, and how to compute a rate of change from two data points.
ObjectiveM.1.9Read2 minExam weightNumbers and Algebra ≈ 53% of Mathematics
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See editions and pricing →What you will be able to do
- Distinguish a ratio from a rate and reduce either to a unit rate.
- Compare two offers stated in different terms using unit rates.
- Calculate a rate of change from two data points.
What the lesson concludes
- A ratio compares like quantities; a rate compares quantities with different units and keeps both units labelled.
- Reduce a rate to a unit rate by dividing numerator and denominator by the same number until the denominator is 1.
- Unit rates let you compare two offers stated in different terms on equal footing.
- Rate of change equals the change in the outcome divided by the change in time, or y2 minus y1 over x2 minus x1.
- Always keep the units attached to a rate. A number without its units is not yet an answer.