document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=82862>Question 82862</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Dear Tutor,<BR>\n" );
document.write( "    Thank-you for taking your time and looking at this problem. I wouldn't be botering you, but I am very stumped. Here it is:<BR>\n" );
document.write( "    Sally drives 720 miles to work and 720 miles back. Her average rate going to work is 12 miles per hour greater than returning. If the entire road trip took 35 hours, what was her average speed going and returning?<BR>\n" );
document.write( "    Thanks again for looking at this. I really need your help!\r<BR>\n" );
document.write( "\n" );
document.write( "Sincerely, Victoria </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #59456 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=59456\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Sally drives 720 miles to work and 720 miles back. Her average rate going to work is 12 miles per hour greater than returning. If the entire road trip took 35 hours, what was her average speed going and returning?<BR>\n" );
document.write( "--------------<BR>\n" );
document.write( "To-work DATA:<BR>\n" );
document.write( "distance = 720 miles ; Rate = x+12 mph ; Time = d/r = 720/(x+12) hrs<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "From-work DAA:<BR>\n" );
document.write( "distance = 720 miles ; Rate = x mph ; Time = d/r = 720/x hrs<BR>\n" );
document.write( "--------------<BR>\n" );
document.write( "EQUATION:<BR>\n" );
document.write( "time + time = 35 hrs<BR>\n" );
document.write( "720/(x+12) + 720/x = 35<BR>\n" );
document.write( "Multiply thru by x(x+12) to get:<BR>\n" );
document.write( "-------<BR>\n" );
document.write( "720x + 720(x+12) = 35x(x+12)<BR>\n" );
document.write( "1440x + 8640 = 35x^2 + 420x<BR>\n" );
document.write( "35x^2-1020x-8640<BR>\n" );
document.write( "7x^2-204x-1728=0<BR>\n" );
document.write( "x = [204+-sqrt90000]/14<BR>\n" );
document.write( "x = [204+-300]/14<BR>\n" );
document.write( "x = 504/14 or -96/14<BR>\n" );
document.write( "Positive solution: x = 36 (Rate driving from work)<BR>\n" );
document.write( "x+12 = 48 (Rate driving to work)<BR>\n" );
document.write( "=====================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H> </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );