standard_description: Use variables to represent two quantities in a real-world problem that change in relationship to one another; write an equation to express one quantity, thought of as the dependent variable, in terms of the other quantity, thought of as the independent variable. Analyze the relationship between the dependent and independent variables using graphs and tables, and relate these to the equation. For example, in a problem involving motion at constant speed, list and graph ordered pairs of distances and times, and write the equation d = 65t to represent the relationship between distance and time.
problem_activity: Task
In a marching band there are 24 trombones and 15 snare drums.
Heather says, “The ratio of trombones to snare drums is 24:15.” Audrey says, “No, the ratio of trombones to snare drums is 8:5.” Who is right, and why?
A different marching band has 30 snare drums, but its trombone to snare drum ratio is the same as the first marching band. How many trombones does it have?
Explain what these ratios all have in common:  8:5, 16:10, 24:15. Create a diagram to support your answer.
Mathematicians call these “equivalent ratios.” Come up with a new set of ratios that are equivalent to 6:21.
Explain in your own words the meaning of “equivalent ratios.”


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