document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1050681>Question 1050681</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A train traveled 120 miles from Station A to Station B. Then, it immediately returned back to Station A, but at an average speed that is 10 mph faster. The total road trip took 7 hours. How long did it take the train to travel from Station B to Station A? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #666277 by </B><A HREF=/tutors/aboutme.mpl?userid=Boreal><B>Boreal(15235)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Boreal><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=Boreal><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=666277\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> speed going was x mph<BR>\n" );
document.write( "time it took to go was 120/x hours, units mi/mi/hr or hr.<BR>\n" );
document.write( "speed back was (x+10) mph and its time was 120/(x+10)<BR>\n" );
document.write( "(120/x)+(120/(x+10)=7<BR>\n" );
document.write( "multiply every thing by x(x+10)<BR>\n" );
document.write( "120(x+10)+120x=7x^2+70x, which is 7*x(x+10)<BR>\n" );
document.write( "240x+1200=7x^2+70x<BR>\n" );
document.write( "7x^2-170x-1200=0<BR>\n" );
document.write( "x=(1/14)(170+/- sqrt(170^2+4(8400)); sqrt is of 62500, and that is 250<BR>\n" );
document.write( "use positive root only<BR>\n" );
document.write( "x=(1/14)(170+250)=(1/14)(420)=30 mph out, 4 hours<BR>\n" );
document.write( "x+10=40 mph back or 3 hours. ANSWER\r<BR>\n" );
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document.write( " </SPAN>\n" );
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