document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=107541>Question 107541</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If 10 pens and 15 markers cost $26, and 5 of the same pens and 10 of the same markers cost $16, find the cost of a pen. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #78317 by </B><A HREF=/tutors/aboutme.mpl?userid=solver91311><B>solver91311(24713)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=solver91311><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=solver91311><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=78317\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This is a 2 linear equations in 2 variables problem.  Let p be the cost of a pen and m be the cost of a marker.\r<BR>\n" );
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document.write( "Eq 1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=10p%2B15m=26 ALIGN=MIDDLE  ALT=\"10p%2B15m=26\"   DISABLED_style= \"max-width:90%; height:auto;\" > and\r<BR>\n" );
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document.write( "Eq 2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5p%2B10m=16 ALIGN=MIDDLE  ALT=\"5p%2B10m=16\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Multiply Eq 2) by -3 and Eq 1) by 2\r<BR>\n" );
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document.write( "Eq 3)  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-15p-30m=-48 ALIGN=MIDDLE  ALT=\"-15p-30m=-48\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Eq 4) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20p%2B30m=52 ALIGN=MIDDLE  ALT=\"20p%2B30m=52\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Then add 3) to 4) term by term:\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5p=4 ALIGN=MIDDLE  ALT=\"5p=4\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=p=0.80 ALIGN=MIDDLE  ALT=\"p=0.80\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "And pens cost 80 cents.\r<BR>\n" );
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document.write( "To check the answer, plug the 80 cents into Eq 1 or 2 to determine that markers cost $1.20, then\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=10%2A0.8%2B15%2A1.20=26 ALIGN=MIDDLE  ALT=\"10%2A0.8%2B15%2A1.20=26\"   DISABLED_style= \"max-width:90%; height:auto;\" >  Check.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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