document.write( "Question 275393: A sales person purchased an automobile that was advertised as averaging 25mi/gal in the city and 40 mi/gal on the highway. A recent sales trip that covered 1800 miles required 51 gallons of gasoline. Assuming that the advertised mileage estimates were correct, how many miles were driven in the city?\r
\n" ); document.write( "\n" ); document.write( "I'm really stumped on how to approach this problems because it seems the answer could possibly have more than one correct answer if there is not a number of highway miles given, or the answer would have a variable in it.
\n" ); document.write( "

Algebra.Com's Answer #200868 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
A sales person purchased an automobile that was advertised as averaging 25mi/gal in the city and 40 mi/gal on the highway.
\n" ); document.write( "-----------------------------
\n" ); document.write( "A recent sales trip that covered 1800 miles required 51 gallons of gasoline.\r
\n" ); document.write( "\n" ); document.write( "Assuming that the advertised mileage estimates were correct, how many miles were driven in the city?
\n" ); document.write( "====
\n" ); document.write( "Let x be the city miles.
\n" ); document.write( "Then 1800-x are the highway miles.
\n" ); document.write( "---
\n" ); document.write( "distance/miles per gallon = gallons
\n" ); document.write( "-----
\n" ); document.write( "Equation:
\n" ); document.write( "gallons + gallons = 51 gallons
\n" ); document.write( "x/25 + (1800-x)/40 = 51 gallons
\n" ); document.write( "---
\n" ); document.write( "Multiply thru by 25*40 to get:
\n" ); document.write( "40x + 25*1800 - 25x = 51*25*40
\n" ); document.write( "15x = 6000
\n" ); document.write( "x = 400 (miles of city driving)
\n" ); document.write( "========================================
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
\n" ); document.write( "
\n" ); document.write( "
\n" );