document.write( "Question 829809: A car gets 17 mpg in the city & 30 mpg on the highway. Say I used 10.636 gallons of gas and got an average of 19 mpg for the trip. How many miles were driven in city and how many in highway? \n" ); document.write( "
Algebra.Com's Answer #500116 by josgarithmetic(39617)\"\" \"About 
You can put this solution on YOUR website!
Recognize this as uniform rates and R*v=u where R is fuel efficiency miles per gallon, v is gallons, u is miles.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " _____________Rate____________gallons volume____________miles distance
\n" ); document.write( "City__________17______________(____)____________________(____)
\n" ); document.write( "HWay__________30______________(____)____________________(____)
\n" ); document.write( "Total____avg, 19_______________10.636___________________(____)\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Begin fillin in what you can:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " _____________Rate____________gallons volume____________miles distance
\n" ); document.write( "City__________17______________(____)____________________(____)
\n" ); document.write( "HWay__________30______________(____)____________________(____)
\n" ); document.write( "Total____avg, 19_______________10.636___________________(19*10.636=202.084)\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Obviously two sums should be formed for the two \"totals\". Let us use x and y for the gallon volumes as shown next:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " _____________Rate____________gallons volume____________miles distance
\n" ); document.write( "City__________17______________(x)____________________(17x)
\n" ); document.write( "HWay__________30______________(y)____________________(30y)
\n" ); document.write( "Total____avg, 19_______________10.636___________________(19*10.636=202.084)\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "SYSTEM OF EQUATIONS:
\n" ); document.write( "------------------------------
\n" ); document.write( "\"x%2By=10.636\" fuel equation
\n" ); document.write( "------------------------------
\n" ); document.write( "\"17x%2B30y=202.084\" miles equation
\n" ); document.write( "------------------------------\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Solve that system and you will have the volume of fuel used in each of City and Highway driving for the trip, and from x and y, compute the miles for City and Highway.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Choose whichever method you like for solving the system.
\n" ); document.write( "
\n" );