4.1+Comparing+Fuel+Economy+0910

S.B.K November 23, 2009 Math 7B Big Idea Many important practical and mathematical applications involve comparing quantities of one kind or another; it is important to know which method to use and how we should use them. Essential Questions: //What methods are there for comparing things?//

// Noted from class: // // Unit Rates: // // Denominator 1 + a label // // Rate Table: // // Cans // || // $ // || // 1 // || // .80 // || // 2 // || // 1.60 // || // 3 // || // 2.40 // || // 4 // || // 3.20 // || //** Problem 4.1 Comparing Fuel Economy **// //** Use the gasoline and mileage data to help settle Madeline and Luis’s argument: **// // Based on the gasoline and mileage data, Madeline’s car is more fuel-efficient. Madeline uses an average of 30.5 miles per gallon, while Luis uses and average of 29 miles per gallon. Madeline used 19 gallons of gas for 580 miles. 580/19= 30.5 miles per gallon. Luis used 15.5 gallons for 452 miles. 452/15.5= 29 miles per gallon. // //** Which car do you think is more fuel-efficient on the highway? Explain how you decided and why you think you are correct: **// // I think Madeline’s car is more fuel-efficient on the highway because she uses less gas. With 19 gallons of gas, she could travel 580 miles, while Luis could travel 554 miles. Madeline uses 30.5 miles per gallon, while Luis uses 29 miles per gallon. // //** Problem 4.1 Follow Up **// //** Would it make sense to use percents to settle this argument? If so, show how, if not, explain why: **// // It would make sense to use percents. Madeline can go 4.6% farther then Luis with the same amount of gas. 29/30.5 = 95.4. 100-95.4 = 4.6%. So, it would make sense to use percents in this situation. //


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