document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=928034>Question 928034</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Zach paddled a canoe 2 miles upstream in a river that has a current of 3 mph. He then turned around and paddled downstream until he reached his original starting place. If the entire trip took him 7 hours, how fast would Zach paddle in still water? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #563422 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=563422\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> x = zach's speed in still water<BR>\n" );
document.write( "y = speed of current = 3 mph<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( "upstream:<BR>\n" );
document.write( "a = time upstream<BR>\n" );
document.write( "a = 2/(x - y)<BR>\n" );
document.write( "a = 2/(x - 3)<BR>\n" );
document.write( "---<BR>\n" );
document.write( "downstream:<BR>\n" );
document.write( "b = time downstream<BR>\n" );
document.write( "b = 2/(x + y)<BR>\n" );
document.write( "b = 2/(x + 3)<BR>\n" );
document.write( "---<BR>\n" );
document.write( "a + b = 7<BR>\n" );
document.write( "2/(x - 3) + 2/(x + 3) = 7<BR>\n" );
document.write( "2(x + 3)/(x - 3)(x + 3) + 2(x - 3)/(x - 3)(x + 3) = 7<BR>\n" );
document.write( "2(x + 3) + 2(x - 3) = 7(x - 3)(x + 3)<BR>\n" );
document.write( "2x + 6 + 2x - 6 = 7(xx - 9)<BR>\n" );
document.write( "4x = 7xx - 63<BR>\n" );
document.write( "7xx - 4x - 63 = 0<BR>\n" );
document.write( "---<BR>\n" );
document.write( "the above quadratic equation is in standard form, with a=7, b=-4 and c=-63<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( "7 -4 -63<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 = 3.29928902<BR>\n" );
document.write( "x = -2.72786044<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 = zach's speed in still water = 3.3 mph<BR>\n" );
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, 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" );
document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );