driving 18K km/yr, 10 km/L @ $0.68/L; new car x km/L more

[Mathamatiques]

Suppose you drive an average of 18000 km/year. With our present car, you can drive 10km per liter of a fuel. You are thinking of buying a new car that you could drive x km farther per liter of fuel. Fuel currently costs $0.68/Liter. If the new car would save $244.80 in yearly fuel costs, find the number of kilometers you could drive the new car per liter of fuel.

Well this is going to be on a test tommorow, and I just can't figure it out! I found out the spending per year on fuel and stuff but just cant make the relation to the equation. Also the unit we are during is Rational Variable Expressions.

Much thanks in advance.

 

[stapel]

Suppose you drive an average of 18000 km/year. With our present car, you can drive 10km per liter of a fuel. You are thinking of buying a new car that you could drive x km farther per liter of fuel. Fuel currently costs $0.68/Liter. If the new car would save $244.80 in yearly fuel costs, find the number of kilometers you could drive the new car per liter of fuel.

At the given rate of fuel consumption, how many liters are you currently using in a year? (Hint: Divide.)

At the given cost per liter, how much are you currently spending for fuel in a year? (Hint: Multiply.)

What expression represents the rate of fuel consumption of the new car? (Hint: Add.)

What expression then represents the number of liters needed for the new car? (Hint: Divide.)

At the given cost per liter, what expression stands for the amount you would spend in a year? (Hint: Multiply.)

You now have a value for the current car and an expression for the new car. You are given their difference. Use this to form an equation. (Hint: Subtract, and set equal to the given difference.)

If you get stuck, please reply showing all of your work and reasoning so far. Thank you!

Eliz.