Unit Rate

Grade 645 minutesCompute unit rates associated with ratios of fractions, including ratios of lengths, areas and other quantities measured in like or different units. For example, if a person walks 1/2 mile in each 1/4 hour, compute the unit rate as the complex fraction 1/2/1/4 miles per hour, equivalently 2 miles per hour. 2. Recognize and represent proportional relationships between quantities. a. Decide whether two quantities are in a proportional relationship, e.g., by testing for equivalent ratios in a table or graphing on a coordinate plane and observing whether the graph is a straight line through the origin. b. Identify the constant of proportionality (unit rate) in tables, graphs, equations, diagrams, and verbal descriptions of proportional relationships. c. Represent proportional relationships by equations. For example, if total cost t is proportional to the number n of items purchased at a constant price p, the relationship between the total cost and the number of items can be expressed as t = pn. d. Explain what a point (x, y) on the graph of a proportional relationship means in terms of the situation, with special attention to the points (0, 0) and (1, r) where r is the unit rate. 3. Use proportional relationships to solve multistep ratio and percent problems. Examples: simple interest, tax, markups and markdowns, gratuities and commissions, fees, percent increase and decrease, percent error.

Learning Objective

I can find the unit rate when given a ratio of two quantities, even if those quantities are fractions.

Practice Questions

This lesson includes 7 practice questions to reinforce learning.

View questions preview

1. Define "unit rate" in your own words.

2. A baker uses 2 cups of flour to make 32 cookies. What is the unit rate of cups of flour per cookie?

3. A car travels 120 miles in 2 hours. What is the unit rate of miles per hour?

...and 4 more questions

Educational Video

Solving unit rates problem | Ratios, proportions, units, and rates | Pre-Algebra | Khan Academy

Khan Academy

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