document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=990545>Question 990545</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A new automobile engine can run on a mixture of gasoline and a substitute fuel. If gas costs $3.25 per gallon and the substitute costs 90¢ per gallon, what percent of a mixture must be substitute to bring the cost down to $3.00 per gallon? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #610554 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/cgi-bin/show-face.mpl?user=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=610554\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+ ALIGN=MIDDLE  ALT=\"+a+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = gallons of gasoline used<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+ ALIGN=MIDDLE  ALT=\"+b+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = gallons of substitute used<BR>\n" );
document.write( "-----------------------------------<BR>\n" );
document.write( "I will say that I am filling a 100 gallon<BR>\n" );
document.write( "tank with the mixture<BR>\n" );
document.write( "---------------------------<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+%2B+b+=+100+ ALIGN=MIDDLE  ALT=\"+a+%2B+b+=+100+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+325a+%2B+90b+%29+%2F+100+=+300+ ALIGN=MIDDLE  ALT=\"+%28+325a+%2B+90b+%29+%2F+100+=+300+\"   DISABLED_style= \"max-width:90%; height:auto;\" > ( in cents )<BR>\n" );
document.write( "----------------------------<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+325a+%2B+90b+=+30000+ ALIGN=MIDDLE  ALT=\"+325a+%2B+90b+=+30000+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+65a+%2B+18b+=+6000+ ALIGN=MIDDLE  ALT=\"+65a+%2B+18b+=+6000+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-------------------------<BR>\n" );
document.write( "Multiply both sides of (1) by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+18+ ALIGN=MIDDLE  ALT=\"+18+\"   DISABLED_style= \"max-width:90%; height:auto;\" > and<BR>\n" );
document.write( "subtract (1) from (2)<BR>\n" );
document.write( "-------------------------<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+65a+%2B+18b+=+6000+ ALIGN=MIDDLE  ALT=\"+65a+%2B+18b+=+6000+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-18a+-+18b+=+-1800+ ALIGN=MIDDLE  ALT=\"+-18a+-+18b+=+-1800+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "---------------------------<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+47a+=+4200+ ALIGN=MIDDLE  ALT=\"+47a+=+4200+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+89.362+ ALIGN=MIDDLE  ALT=\"+a+=+89.362+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+%2B+b+=+100+ ALIGN=MIDDLE  ALT=\"+a+%2B+b+=+100+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+10.638+ ALIGN=MIDDLE  ALT=\"+b+=+10.638+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "10.638 % of substitute and 89.362 % of gasoline <BR>\n" );
document.write( "must be used<BR>\n" );
document.write( "--------------------<BR>\n" );
document.write( "check answer:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+325a+%2B+90b+%29+%2F+100+=+300+ ALIGN=MIDDLE  ALT=\"+%28+325a+%2B+90b+%29+%2F+100+=+300+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+325%2A89.362+%2B+90%2A10.638+%29+%2F+100+=+300+ ALIGN=MIDDLE  ALT=\"+%28+325%2A89.362+%2B+90%2A10.638+%29+%2F+100+=+300+\"   DISABLED_style= \"max-width:90%; height:auto;\" > <BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=++29042.65+%2B+957.42+=+30000+ ALIGN=MIDDLE  ALT=\"++29042.65+%2B+957.42+=+30000+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+30000.07+=+30000+ ALIGN=MIDDLE  ALT=\"+30000.07+=+30000+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "error due to rounding off<BR>\n" );
document.write( "  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );