Math Problem Statement

You are running a fuel economy study. One of the cars you find is blue. It can travel 35 1/2 miles on 1 1/4 gallons of gasoline. Another car is red. It can travel 28 4/5 miles on 4/5 gallon of gasoline. What is the unit rate for miles per gallon for each car? Which car could travel the greater distance on 1 gallon of gasoline?

Solution

To solve the problem in the image:

Step 1: Blue Car's Unit Rate

The blue car travels 351235 \frac{1}{2} miles on 1141 \frac{1}{4} gallons of gasoline.

  1. Convert the mixed numbers into improper fractions: 3512=712,114=5435 \frac{1}{2} = \frac{71}{2}, \quad 1 \frac{1}{4} = \frac{5}{4}

  2. To find the unit rate (miles per gallon), divide the total miles by the total gallons: Unit rate for blue car=71254=712×45=28410=28.4miles per gallon.\text{Unit rate for blue car} = \frac{\frac{71}{2}}{\frac{5}{4}} = \frac{71}{2} \times \frac{4}{5} = \frac{284}{10} = 28.4 \, \text{miles per gallon}.

Step 2: Red Car's Unit Rate

The red car travels 284528 \frac{4}{5} miles on 45\frac{4}{5} gallons of gasoline.

  1. Convert the mixed number into an improper fraction: 2845=144528 \frac{4}{5} = \frac{144}{5}

  2. To find the unit rate (miles per gallon), divide the total miles by the total gallons: Unit rate for red car=144545=1445×54=1444=36miles per gallon.\text{Unit rate for red car} = \frac{\frac{144}{5}}{\frac{4}{5}} = \frac{144}{5} \times \frac{5}{4} = \frac{144}{4} = 36 \, \text{miles per gallon}.

Step 3: Compare

  • Blue car: 28.4miles per gallon28.4 \, \text{miles per gallon}
  • Red car: 36miles per gallon36 \, \text{miles per gallon}

Conclusion: The red car can travel a greater distance on 1 gallon of gasoline.


Let me know if you'd like a deeper explanation or visualized calculations!
Here are five related questions to consider:

  1. How would these calculations change if we used different units (e.g., kilometers)?
  2. What happens if the fuel consumption of one car is doubled?
  3. How can mixed fractions affect real-world problem-solving accuracy?
  4. Can we model these unit rates graphically to show their differences?
  5. What external factors might affect real-world fuel efficiency?

Tip: Always simplify fractions in real-world calculations to make interpretation easier!

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Math Problem Analysis

Mathematical Concepts

Fractions
Division
Unit Rates

Formulas

Unit rate formula: distance traveled ÷ gallons of gasoline

Theorems

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Suitable Grade Level

Grades 5-7