document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=934607>Question 934607</A>: <I><SPAN STYLE=\"word-break: break-all;\"> To train for the running of a triathlon, Jerri jogs 1 hour each day over the same 7 mile course. Four miles of the course is downhill, whereas the other 3 miles is on level ground. Jerri figures that she runs 2 miles per hour faster downhill than she runs on level ground. Find the rate at which Jerri runs on level ground.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #567596 by </B><A HREF=/tutors/aboutme.mpl?userid=TimothyLamb><B>TimothyLamb(4379)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=TimothyLamb><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=TimothyLamb><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=567596\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x = speed on level ground<BR>\n" );
document.write( "y = speed downhill<BR>\n" );
document.write( "y = x + 2<BR>\n" );
document.write( "t = time downhill<BR>\n" );
document.write( "---<BR>\n" );
document.write( "s = d/t<BR>\n" );
document.write( "t = d/s<BR>\n" );
document.write( "---<BR>\n" );
document.write( "time downhill:<BR>\n" );
document.write( "t = 4/y<BR>\n" );
document.write( "t = 4/(x + 2)<BR>\n" );
document.write( "---<BR>\n" );
document.write( "time on level ground:<BR>\n" );
document.write( "1 - t = 3/x<BR>\n" );
document.write( "t = 1 - 3/x<BR>\n" );
document.write( "---<BR>\n" );
document.write( "equate times:<BR>\n" );
document.write( "4/(x + 2) = 1 - 3/x<BR>\n" );
document.write( "4/(x + 2) = x/x - 3/x<BR>\n" );
document.write( "4/(x + 2) = (x - 3)/x<BR>\n" );
document.write( "4x = (x - 3)(x + 2)<BR>\n" );
document.write( "4x = xx + 2x - 3x - 6<BR>\n" );
document.write( "xx - 5x - 6 = 0<BR>\n" );
document.write( "---<BR>\n" );
document.write( "the above quadratic equation is in standard form, with a=1, b=-5 and c=-6<BR>\n" );
document.write( "---<BR>\n" );
document.write( "to solve the quadratic equation, by using the quadratic formula, copy and paste this:<BR>\n" );
document.write( "1 -5 -6<BR>\n" );
document.write( "into this solver: https://sooeet.com/math/quadratic-equation-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "the quadratic has two real roots at:<BR>\n" );
document.write( "---<BR>\n" );
document.write( "x = 6<BR>\n" );
document.write( "x = -1<BR>\n" );
document.write( "---<BR>\n" );
document.write( "the negative root doesn't fit the problem statement, so use the positive root:<BR>\n" );
document.write( "---<BR>\n" );
document.write( "answer:<BR>\n" );
document.write( "x = speed on level ground = 6 mph<BR>\n" );
document.write( "y = speed downhill = 8 mph<BR>\n" );
document.write( "---<BR>\n" );
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document.write( "---<BR>\n" );
document.write( "Solve and graph linear equations:<BR>\n" );
document.write( "https://sooeet.com/math/linear-equation-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve quadratic equations with quadratic formula:<BR>\n" );
document.write( "https://sooeet.com/math/quadratic-formula-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Solve systems of linear equations up to 6-equations 6-variables:<BR>\n" );
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document.write( "--- </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );