Final answer:
The new car would represent approximately a 60.71% increase in miles per gallon of gasoline over Sadie's current car, which is a significant improvement in fuel efficiency.
Step-by-step explanation:
Sadie is considering a change from her current car that achieves 28 miles per gallon (mpg) to a newer car with a fuel economy of 45 mpg. To find the percent increase in fuel efficiency, we can use the following formula:
Percent Increase = ((New Value - Old Value) / Old Value) * 100
Plugging in the values for Sadie's cars, we get:
Percent Increase = ((45 mpg - 28 mpg) / 28 mpg) * 100
Percent Increase = (17 mpg / 28 mpg) * 100
Percent Increase = 0.6071 * 100
Percent Increase = 60.71%
So, the new car would represent approximately a 60.71% increase in fuel efficiency over Sadie's current car.