document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=828314>Question 828314</A>: <I><SPAN STYLE=\"word-break: break-all;\"> It takes Brian 15 hours longer to build a model car than it takes John. If they work together, they can build the model car in 4 hours. Using complete sentences, explain each step in figuring out how to determine the time it would take Brian to build the car on his own.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #499304 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=499304\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Add Brian's rate of working and John's<BR>\n" );
document.write( "rate of working to get their rate working<BR>\n" );
document.write( "together.<BR>\n" );
document.write( "--------------------------<BR>\n" );
document.write( "If <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+ ALIGN=MIDDLE  ALT=\"+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" > equals John's time in hours to build <BR>\n" );
document.write( "the model, then Brian's time to build the model is <BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+%2B+15+ ALIGN=MIDDLE  ALT=\"+t+%2B+15+\"   DISABLED_style= \"max-width:90%; height:auto;\" > hours<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "John's rate is ( one model built ) / ( t hours )<BR>\n" );
document.write( "Brian's rate is ( one model built ) / ( t + 15 hours )<BR>\n" );
document.write( "Their rate working together is:<BR>\n" );
document.write( "( one model built ) / ( 4 hours )<BR>\n" );
document.write( "---------------------------<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2Ft+%2B+1%2F%28t%2B15%29+=+1%2F4+ ALIGN=MIDDLE  ALT=\"+1%2Ft+%2B+1%2F%28t%2B15%29+=+1%2F4+\"   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=+4t%2A%28+t%2B15+%29+ ALIGN=MIDDLE  ALT=\"+4t%2A%28+t%2B15+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+4%2A%28+t%2B15+%29+%2B+4t+=+t%2A%28+t%2B15+%29+ ALIGN=MIDDLE  ALT=\"+4%2A%28+t%2B15+%29+%2B+4t+=+t%2A%28+t%2B15+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+4t+%2B+60+%2B+4t+=+t%5E2+%2B+15t+ ALIGN=MIDDLE  ALT=\"+4t+%2B+60+%2B+4t+=+t%5E2+%2B+15t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t%5E2+%2B+7t+-+60+=+0+ ALIGN=MIDDLE  ALT=\"+t%5E2+%2B+7t+-+60+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+%28+t+%2B+12+%29%2A%28+t+-+5+%29+=+0+ ALIGN=MIDDLE  ALT=\"+%28+t+%2B+12+%29%2A%28+t+-+5+%29+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" > ( by inspection )<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+5+ ALIGN=MIDDLE  ALT=\"+t+=+5+\"   DISABLED_style= \"max-width:90%; height:auto;\" > ( I can't use the negative root )<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+%2B+15+=+5+%2B+15+ ALIGN=MIDDLE  ALT=\"+t+%2B+15+=+5+%2B+15+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+%2B+15+=+20+ ALIGN=MIDDLE  ALT=\"+t+%2B+15+=+20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Brian's time to build the car on his own is 20 hours<BR>\n" );
document.write( "-------------------<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2Ft+%2B+1%2F%28t%2B15%29+=+1%2F4+ ALIGN=MIDDLE  ALT=\"+1%2Ft+%2B+1%2F%28t%2B15%29+=+1%2F4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+1%2F5+%2B+1%2F20+=+1%2F4+ ALIGN=MIDDLE  ALT=\"+1%2F5+%2B+1%2F20+=+1%2F4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+4%2F20+%2B+1%2F20+=+5%2F20+ ALIGN=MIDDLE  ALT=\"+4%2F20+%2B+1%2F20+=+5%2F20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+5%2F20+=+5%2F20+ ALIGN=MIDDLE  ALT=\"+5%2F20+=+5%2F20+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK<BR>\n" );
document.write( "  </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );