SOLUTION: A family has two cars. The first car has a fuel efficiency of 40 miles per gallon of gas and the second has a fuel efficiency of 25 miles per gallon of gas. During one particular w

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Question 1168128: A family has two cars. The first car has a fuel efficiency of 40 miles per gallon of gas and the second has a fuel efficiency of 25 miles per gallon of gas. During one particular week, the two cars went a combined total of 1575 miles, for a total gas consumption of 45 gallons. How many gallons were consumed by each of the two cars that week?
Found 2 solutions by ikleyn, josgarithmetic:
Answer by ikleyn(52785) About Me  (Show Source):
You can put this solution on YOUR website!
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A family has two cars. The first car has a fuel efficiency of 40 miles per gallon of gas
and the second has a fuel efficiency of 25 miles per gallon of gas.
During one particular week, the two cars went a combined total of 1575 miles, for a total gas consumption of 45 gallons.
How many gallons were consumed by each of the two cars that week?
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Let x be the number of gallons were consumed by the first car.

Then the number of gallons consumed by the second car is  (45-x).


The distance traveled by the first car is 40x miles.

The distance traveled by the second car is 25*(45-x) miles.


The total distance equation is

    40x + 25*(45-x) = 1575  miles.


From this equation, express x and calculate

    x = %281575+-+25%2A45%29%2F%2840-25%29 = 30.


ANSWER.  The first car consumed 30 gallons of fuel.  The second car consumed the rest (45-30) = 15 gallons.

Solved.



Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
v, the gallons that first car used
 

            fuel efficency     volume        miles
Firstcar       40                v           40v
Secondcar      25               45-v         25(45-v)
Totals                          45           1575

First solve for first car's fuel volume used v, in gallons:
40v%2B25%2845-v%29=1575
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