document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=825589>Question 825589</A>: <I><SPAN STYLE=\"word-break: break-all;\"> with a head wind, a plane traveled 1000 miles in 4 hours. with the same wind as a tail wind, the return trip took 3 hours 20 minutes. find the wind speed. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #497416 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=497416\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> ---<BR>\n" );
document.write( "x = airplane speed<BR>\n" );
document.write( "y = wind speed<BR>\n" );
document.write( "---<BR>\n" );
document.write( "s = d/t<BR>\n" );
document.write( "---<BR>\n" );
document.write( "head:<BR>\n" );
document.write( "x - y = 1000/4<BR>\n" );
document.write( "---<BR>\n" );
document.write( "tail:<BR>\n" );
document.write( "x + y = 1000/(3+(20/60))<BR>\n" );
document.write( "---<BR>\n" );
document.write( "system:<BR>\n" );
document.write( "x - y = 1000/4<BR>\n" );
document.write( "x + y = 1000/(3+(20/60))<BR>\n" );
document.write( "---<BR>\n" );
document.write( "put the system of linear equations into standard form<BR>\n" );
document.write( "---<BR>\n" );
document.write( "x - y = 250<BR>\n" );
document.write( "x + y = 300<BR>\n" );
document.write( "---<BR>\n" );
document.write( "copy and paste the above linear system in standard form into this matrix-method solver:<BR>\n" );
document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php<BR>\n" );
document.write( "---<BR>\n" );
document.write( "solution:<BR>\n" );
document.write( "x = airplane speed = 275 mph<BR>\n" );
document.write( "y = wind speed = 25 mph<BR>\n" );
document.write( "---<BR>\n" );
document.write( "system matrix<BR>\n" );
document.write( "1 -1<BR>\n" );
document.write( "1 1<BR>\n" );
document.write( "---<BR>\n" );
document.write( "inverse of system matrix<BR>\n" );
document.write( "0.5 0.5<BR>\n" );
document.write( "-0.5 0.5<BR>\n" );
document.write( "---<BR>\n" );
document.write( "determinant of system matrix = 2<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 4-equations 4-variables:<BR>\n" );
document.write( "https://sooeet.com/math/system-of-linear-equations-solver.php </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );