suppose you drive and average of 15,000 miles per year, and your car gets 24 miles per gallon. Suppose gasoline costs $3.60 per gallon.

Question

 

a.)You plan to trade in your car that gets x amount of more miles per gallon. Write an expression to represent the new yearly cost of gasoline. 

b.) Suppose you can save $600 per year with the new car. How may miles per gallon does the new car get?

Answer 1

The new yearly cost for gas is (15,000mi/yr.)/(24mi/gal + x) = gallons per year * $3.60

 

If you save $600 a year, you will get the following equation:

 

$2250 - $600 = $3.60(15,000/24 +x) 

 

x should equal 8.72, which gives us a new miles per gallon of 32.72.

 

 

 

Answer 2

$ for gasoline in a year = (15000/24+x) (3.60)

 

$ for gasoline in a year = (15000/24) (3.60) = 2250 

 

If we are saving $600, then we spent in a year $1650, therefore

 

$1650= (15000/24+x) (3.60)

 

$1650=54000/24+x

 

24 + x = 32.73

 

x = 32.73-24

 

x=8.72

 

Miles per gallon 32.73 (because we said it is 24 + x --> so if x is 8.72 then it has to be 32.73)