Unit 2, Lesson 20
Solving Rate Problems
Accelerated 6
Preparation
Lesson Narrative
In this lesson, students solve problems that reward finding and making sense of unit rates. All problems use the Burj Khalifa—the tallest building in the world as of 2023—as a context. Solving them requires students to make sense of and talk about rates in terms of the situation, giving students opportunities to apply and deepen their understanding from earlier lessons.
Students reason about two rates—a rate for climbing the building and a rate for washing all of its windows. In the activity about climbing, students work with smaller values that are related by familiar whole-number factors or by benchmark fractions. The problems are well defined. In the activity about window washing, students need to request one of the values, the number of windows on the Burj Khalifa, which is a large number and not a multiple of either value in the given ratio. Possible solution paths may not be as apparent—an opportunity for students to make sense of problems and persevere in solving them (MP1).
- Choose a strategy to solve problems involving rates and explain (orally, in writing, and through other representations) the solution method.
- Evaluate (orally) the usefulness of calculating a rate per 1 when solving problems involving unfamiliar rates.
Let’s investigate the Burj Khalifa building.
Required Materials
Activity 3
Required Preparation
All computations in this lesson can be done with methods that students learned up through grade 5. However, you may wish to provide access to calculators to deemphasize computation and allow students to focus on reasoning about the context.