SOLUTION: A family has two cars. the first car has a fuel efficiency of 25 miles per gallon of gas and the second has a fuel efficiency of 15 miles per gallon of gas. during one particular w

Algebra ->  Coordinate Systems and Linear Equations  -> Lessons  -> Linear Equations Lesson -> SOLUTION: A family has two cars. the first car has a fuel efficiency of 25 miles per gallon of gas and the second has a fuel efficiency of 15 miles per gallon of gas. during one particular w      Log On


   

Question 1180010: A family has two cars. the first car has a fuel efficiency of 25 miles per gallon of gas and the second has a fuel efficiency of 15 miles per gallon of gas. during one particular week, the two cars went a combined total of 1325 miles, for a gas consumption of 65 gallons. How many gallons were consumed by each of the two cars that week?
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
%28fuelefficiency%29%28volume%29=distance 
               Efficiency     Volume        DISTANCES

onecar            25            v            25v

secondcar         15          65-v           15(65-v)

totals                         65             1325

Can you see what to do?

Answer by ikleyn(52793) About Me  (Show Source):
You can put this solution on YOUR website!
.
A family has two cars. the first car has a fuel efficiency of 25 miles per gallon of gas
and the second has a fuel efficiency of 15 miles per gallon of gas.
during one particular week, the two cars went a combined total of 1325 miles,
for a gas consumption of 65 gallons. How many gallons were consumed by each of the two cars that week?
~~~~~~~~~~~~~~~ 

Let x be the number of gallons were consumed by the first car.

Then the number of gallons consumed by the second car is  (65-x).


The distance traveled by the first car is 25x miles.

The distance traveled by the second car is 15*(65-x) miles.


The total distance equation is

    25x + 15*(65-x) = 1325  miles.


From this equation, express x and calculate

    x = %281325+-+15%2A65%29%2F%2825-15%29 = 35.


ANSWER.  The first car consumed 35 gallons of fuel.  The second car consumed the rest (65-35) = 30 gallons.

Solved.

--------------

See the lesson
    - Miles per gallon effectiveness and moving car
in this site.