SOLUTION: The cost of driving your vehicle can be calculated using the following equation: Fuel cost for one year = (miles driven * price per gallon) ÷ (fuel effieciency rate). If you dro

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Question 572899: The cost of driving your vehicle can be calculated using the following equation:
Fuel cost for one year = (miles driven * price per gallon) ÷ (fuel effieciency rate). If you drove 22,500 miles, paid $225 per gallon of gasoline, and spent a total of $2025 on gasoline, what is the fuel effieciency rate of your car? How much would you have saved if your cars's fuel efficiency rate were 35 miles per gallon?
My grade is depending on these questions and I am very lost, please help me if you can. I would greatly appreciate it.

Answer by mathsmiles(68) About Me  (Show Source):
You can put this solution on YOUR website!
Fuel cost for one year = $2025
Price per gallon = $225
Miles driven = 22,500

Fuel cost for one year = (miles driven * price per gallon) / (fuel efficiency rate)
You have everything but the fuel efficiency rate already. Just need to solve for that. Let's call that E

So, substituting,
2025 = (22500 * 2.25) / E.
2025 = (50625) / E
To get E in the numerator, we need to multiply each side by E.
2025 * E = 50625
Now divide both sides by 2025 to get E alone.

E = 25. Fuel efficiency is 25.

The second part of the question gives you a new E, but wants us to calculate the new fuel cost for one year. So back to the formula:
Fuel cost for one year = (miles driven * price per gallon) / (fuel efficiency rate)
Let C = cost for one year
C = (22500 * 2.25) / 35
C = 1446.43
If the fuel efficiency were 35, the cost per year would have been $1446.43.

The savings would have been: $2025 - $1446.43 = $578.57