document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=956520>Question 956520</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Suppose that Helena and Corrine can clean their entire house in 7 hours, while their little brother, William, just by being around, can completely mess it up in only 2 hours. If Helena and Corrine clean the house while William is at his grandma’s house. How long will it take for the house to be in shambles again if Helena and Corrine clean the house again the moment William returns to their house? <BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #584449 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=584449\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Their rate of cleaning:<BR>\n" );
document.write( "[ 1 house cleaned ] / [ 7 hrs ]<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2F7+ ALIGN=MIDDLE  ALT=\"+1%2F7+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "William's rate of messing it up:<BR>\n" );
document.write( "[ 1 house messed up ] / [ 2 hrs ]<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-1%2F2+ ALIGN=MIDDLE  ALT=\"+-1%2F2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "( the minus sign is needed because  this<BR>\n" );
document.write( "is the opposite of cleaning the house )<BR>\n" );
document.write( "------------------------------------<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2Ft+ ALIGN=MIDDLE  ALT=\"+1%2Ft+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = rate of getting messed up<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2F7+-+1%2F2+=+1%2Ft+ ALIGN=MIDDLE  ALT=\"+1%2F7+-+1%2F2+=+1%2Ft+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both sides by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+14t+ ALIGN=MIDDLE  ALT=\"+14t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2t+-+7t+=+14+ ALIGN=MIDDLE  ALT=\"+2t+-+7t+=+14+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+-5t+=+14+ ALIGN=MIDDLE  ALT=\"+-5t+=+14+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+-2.8+ ALIGN=MIDDLE  ALT=\"+t+=+-2.8+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "--------------<BR>\n" );
document.write( "In 2.8 hrs, the house is messed up again\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );