document.write( "Question 175999: In a family there are two cars. In a given week, the first car gets an average of 40 miles per gallon, and the second car gets 35 miles per gallon. The two cars combined drive a total of 1300 miles in that week, for a total gas consumption of 35 gallons. How many gallons were consumed by each of the two cars that week?
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Algebra.Com's Answer #131147 by ankor@dixie-net.com(22740)\"\" \"About 
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n a family there are two cars. In a given week, the first car gets an average of 40 miles per gallon, and the second car gets 35 miles per gallon. The two cars combined drive a total of 1300 miles in that week, for a total gas consumption of 35 gallons. How many gallons were consumed by each of the two cars that week?
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\n" ); document.write( "Let x = no. of gallons consumed by the 1st car
\n" ); document.write( "Let y = no. of gallons consumed by the 2nd
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\n" ); document.write( "Total gallons equation:
\n" ); document.write( "x + y = 35
\n" ); document.write( "or
\n" ); document.write( "y = (35-x); use this for substitution
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\n" ); document.write( "Miles driven equation
\n" ); document.write( "40x + 35y = 1300
\n" ); document.write( "Substitute (35-x) for y
\n" ); document.write( "40x + 35(35-x) = 1300
\n" ); document.write( "40x + 1225 - 35x = 1300
\n" ); document.write( "40x - 35x = 1300 - 1225
\n" ); document.write( "5x = 75
\n" ); document.write( "x = \"75%2F5\"
\n" ); document.write( "x = 15 gal used by the 1st car
\n" ); document.write( "and
\n" ); document.write( "35 - 15 = 20 gal used by the 2nd car
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\n" ); document.write( "Check solution in the miles equation
\n" ); document.write( "40(15) + 35(20) =
\n" ); document.write( "600 + 700 = 1300 mi confirms our solutions \n" ); document.write( "
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