document.write( "Question 800726: Martina drove to the mountains last weekend. There was heavy traffic on the way there, and the trip 8 took hours. When Martina drove home, there was no traffic and the trip only 5 took hours. If her average rate was 21 miles per hour faster on the trip home, how far away does Martina live from the mountains? \n" ); document.write( "

Algebra.Com's Answer #483228 by mananth(16946) $\"\"$ $\"About$

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let Martina live x miles from the mountains\r
\n" ); document.write( "\n" ); document.write( "Let her rate to mountains be y\r
\n" ); document.write( "\n" ); document.write( "t=d/r\r
\n" ); document.write( "\n" ); document.write( "x/y = 8
\n" ); document.write( "x=8y\r
\n" ); document.write( "\n" ); document.write( "Return trip 5 hours
\n" ); document.write( "rate = y+21\r
\n" ); document.write( "\n" ); document.write( "x/(y+21) =5\r
\n" ); document.write( "\n" ); document.write( "substitute x
\n" ); document.write( "8y/(y+21)=5\r
\n" ); document.write( "\n" ); document.write( "8y=5y+105\r
\n" ); document.write( "\n" ); document.write( "8y-5y=105
\n" ); document.write( "3y=105
\n" ); document.write( "y= 105/3
\n" ); document.write( "y=35\r
\n" ); document.write( "\n" ); document.write( "x=8y
\n" ); document.write( "x=8*35= 280 miles\r
\n" ); document.write( "\n" ); document.write( "distance to the mountain = 280 miles \n" ); document.write( "

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