document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=862073>Question 862073</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am helping my daughter do her homework and we are stuck on this one. Please help me explain it.\r<BR>\n" );
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document.write( "Twin brothers, person A and person B can mow the lawn together in 20 minutes.  Person A can mow the lawn by himself in 9 minutes less than it would take person B.  How long would it take person B to mow the lawn by himself?\r<BR>\n" );
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document.write( "Many thanks,<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #519441 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=519441\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A & B can mow the lawn in 20 minutes\r<BR>\n" );
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document.write( "consider mowing the lawn is one job\r<BR>\n" );
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document.write( "so they do 1/20 of the job in 1 minute\r<BR>\n" );
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document.write( "let B take x minutes to do the job alone<BR>\n" );
document.write( "he does 1/x of the job in 1 minute\r<BR>\n" );
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document.write( "A takes 9 minutes less than B  (x-9)\r<BR>\n" );
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document.write( "So A does 1/(x-9) of the job in 1 minute\r<BR>\n" );
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document.write( "Together\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2Fx+%2B+1%2F%28x-9%29+=+1%2F20 ALIGN=MIDDLE  ALT=\"1%2Fx+%2B+1%2F%28x-9%29+=+1%2F20\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "LCM 20x(x-9)\r<BR>\n" );
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document.write( "20(x-9)+20x=x(x-9)\r<BR>\n" );
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document.write( "20x-180+20x=x^2-9x\r<BR>\n" );
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document.write( "x^2-49x+!80=0\r<BR>\n" );
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document.write( "x^2-45x-4x+!80=0\r<BR>\n" );
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document.write( "x(x-45)-4(x-45)=0\r<BR>\n" );
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document.write( "(x-45)(x-4)=0\r<BR>\n" );
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document.write( "x=45 OR 4\r<BR>\n" );
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document.write( "B takes 45 minutes to mow the lawn alone\r<BR>\n" );
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document.write( "so he does 1/9 of the job in 1 minute\r<BR>\n" );
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