document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=347354>Question 347354</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A family drove 1512 miles to their vacation lodge. Because of increased traffic density, their average speed on the return trip was decreased by 7 miles per hour and the trip took 3 hours longer. Determine their original average speed on the way to the lodge. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #248378 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=248378\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A family drove 1512 miles to their vacation lodge. Because of increased traffic density, their average speed on the return trip was decreased by 7 miles per hour and the trip took 3 hours longer. Determine their original average speed on the way to the lodge.<BR>\n" );
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document.write( "To lodge DATA:<BR>\n" );
document.write( "rate = x mph ; distance = 1512 miles ; time = d/r = 1512/x hrs<BR>\n" );
document.write( "---------------------------------------------------<BR>\n" );
document.write( "From lodge DATA:<BR>\n" );
document.write( "rate = x-7 mph ; distance = 1512 miles ; time = 1512/(x-7) hrs<BR>\n" );
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document.write( "Equation:<BR>\n" );
document.write( "from time - to time = 3 hrs<BR>\n" );
document.write( "1512/(x-7) -1512/x = 3<BR>\n" );
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document.write( "1512x - 1512(x-7) = 3x(x-7)<BR>\n" );
document.write( "---<BR>\n" );
document.write( "1512*7 = 3x^2-21x<BR>\n" );
document.write( "x^2 - 7x - 3528 = 0<BR>\n" );
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document.write( "(x-63)(xx+56) = 0<BR>\n" );
document.write( "Positive solution:<BR>\n" );
document.write( "x = 63 mph (rate to the lodge)<BR>\n" );
document.write( "x-7 = 56 mph (rate from the lodge)<BR>\n" );
document.write( "====================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( "===================== </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );