document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=376475>Question 376475</A>: <I><SPAN STYLE=\"word-break: break-all;\"> It takes Joe 12 hours to paint a fence, but Bob can do the job in 9 hours.  How long does Joe work by himself before being joined by Sam if they finish the job working 3 hours together?\r<BR>\n" );
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document.write( "I've tried setting up a system of equations, but am not having much luck.  I think that the first equation is x/12 + y/9 = 1, with x being the number of hours Joe works and y the number of hours Bob works, but I can't figure out the second equation. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #267839 by </B><A HREF=/tutors/aboutme.mpl?userid=nerdybill><B>nerdybill(7384)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=nerdybill><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=nerdybill><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=267839\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> It takes Joe 12 hours to paint a fence, but Bob can do the job in 9 hours. How long does Joe work by himself before being joined by Sam if they finish the job working 3 hours together? <BR>\n" );
document.write( "Let x = number of hours Joe works by himself<BR>\n" );
document.write( "then<BR>\n" );
document.write( "\"portion of work by Joe\" + \"work together\" = \"total job\"<BR>\n" );
document.write( "x/12 + 3(1/12 + 1/9) = 1<BR>\n" );
document.write( "x/12 + (1/4 + 1/3) = 1<BR>\n" );
document.write( "multiplying both sides by 12:<BR>\n" );
document.write( "x + (3 + 4) = 12<BR>\n" );
document.write( "x + 7 = 12<BR>\n" );
document.write( "x = 5 hours<BR>\n" );
document.write( " </SPAN>\n" );
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