document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=132068>Question 132068</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The sum of Joe's age and Mary's age is 60 years. Ten years ago, Joe was 3 times as old as Mary was then. How old is each now? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #96447 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=96447\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Joe is x years old<BR>\n" );
document.write( "Mary is y years old<BR>\n" );
document.write( "We are given that <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%2By=60 ALIGN=MIDDLE  ALT=\"x%2By=60\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Ten years ago, Joe was x - 10 years old and Mary was y - 10 years old.<BR>\n" );
document.write( "We are given that <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x-10=3%28y-10%29 ALIGN=MIDDLE  ALT=\"x-10=3%28y-10%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Put the second relationship into standard form (<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=ax%2Bby=c ALIGN=MIDDLE  ALT=\"ax%2Bby=c\"   DISABLED_style= \"max-width:90%; height:auto;\" >)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x-10=3%28y-10%29 ALIGN=MIDDLE  ALT=\"x-10=3%28y-10%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x-10=3y-30 ALIGN=MIDDLE  ALT=\"x-10=3y-30\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x-3y=-30%2B10 ALIGN=MIDDLE  ALT=\"x-3y=-30%2B10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x-3y=-20 ALIGN=MIDDLE  ALT=\"x-3y=-20\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Now we have two equations in standard form:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%2By=60 ALIGN=MIDDLE  ALT=\"x%2By=60\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x-3y=-20 ALIGN=MIDDLE  ALT=\"x-3y=-20\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Multiply the second equation by -1:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-x%2B3y=20 ALIGN=MIDDLE  ALT=\"-x%2B3y=20\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Add the first equation to the second, term by term:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=0x%2B4y=80 ALIGN=MIDDLE  ALT=\"0x%2B4y=80\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Divide by the coefficient on y:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y=20 ALIGN=MIDDLE  ALT=\"y=20\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Therefore Mary is 20 years old now.  That means that Joe is 40 years old now (60 - 20).  Ten years ago, Joe would have been 30 and Mary would have been 10, and 30 is 3 times 10.  Answer checks. </SPAN>\n" );
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