document.write( "Question 781967: An automobile engine can run on a mixture of gasoline and a substitute fuel. If gas costs $3.45 per gallon and the substitute fuel costs $2 per gallon, what percent of a mixture must be substitute fuel to bring the cost down to $2.58 per gallon?
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Algebra.Com's Answer #476372 by ankor@dixie-net.com(22740)\"\" \"About 
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If gas costs $3.45 per gallon and the substitute fuel costs $2 per gallon, what percent of a mixture must be substitute fuel to bring the cost down to $2.58 per gallon?
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\n" ); document.write( "We can make 10 gal of the mixture and find the percent from that
\n" ); document.write( "Let x = amt of 3.45 fuel
\n" ); document.write( "then
\n" ); document.write( "(10-x) = amt of 2.00 fuel
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\n" ); document.write( "3.45x + 2(10-x) = 2.58(10)
\n" ); document.write( "3.45x + 20 - 2x = 25.8
\n" ); document.write( "3.45x - 2x = 25.8 - 20
\n" ); document.write( "1.45x = 5.8
\n" ); document.write( "x = 5.8/1.45
\n" ); document.write( "x = 4 gal of 3.45 fuel
\n" ); document.write( "then
\n" ); document.write( "10-4 = 6 gal of $2 fuel
\n" ); document.write( "Obviously that is 60% \n" ); document.write( "
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