Question 1122623
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 During one particular week, the first car consumed 25 gallons of gas and the second consumed 40 gallons of gas. The two cars drove a combined total of 1600 miles, and the sum of their fuel efficiencies was 55 miles per gallon. What were the fuel efficiencies of each of the cars that week?
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{{{R=D/V}}}, fuel efficiency R in miles per gallons
<pre>
              FUEL EFFICIENCY   VOLUME       DISTANCE

FirstCar         x               25            25x

SecondCar        y               40            40y

Totals          55               65            1600
</pre>
{{{system(x+y=55,25x+40y=1600)}}}


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{{{5x+8y=320}}}


{{{5(55-y)+8y=320}}}

{{{275-5y+8y=320}}}

{{{3y=320-275}}}

{{{highlight(y=15)}}}-----------miles per gallon, the SecondCar

{{{highlight(x=40)}}}-------------------FirstCar
.