document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=933809>Question 933809</A>: <I><SPAN STYLE=\"word-break: break-all;\">  A jet plane flying with the wind went 2060 mi in 4 h. Flying against the wind, the plane could only fly 1800 mi in the same amount of time. Find the rate of the plane in calm air and the rate of the wind.  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #567049 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39620)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><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=567049\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Questions 933811, 933810, and 933809 are the same fundamental problem as different examples.\r<BR>\n" );
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document.write( "<i>A vehicle traveling with the wind went w miles in t hours. Traveling against the wind, the vehicle could only go c miles in the same amount of time. Find the rate of the vehicle in calm air and the rate of the wind.</i>\r<BR>\n" );
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document.write( "The unknowns are r for rate in calm air, and n for the rate of the wind.\r<BR>\n" );
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document.write( "____________rate_______time_______distance<BR>\n" );
document.write( "WITH______r+n________t___________w<BR>\n" );
document.write( "AGNST____r-n__________t___________c\r<BR>\n" );
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document.write( "The equations are <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28r%2Bn%29%2At=w ALIGN=MIDDLE  ALT=\"%28r%2Bn%29%2At=w\"   DISABLED_style= \"max-width:90%; height:auto;\" > and  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28r-n%29%2At=c ALIGN=MIDDLE  ALT=\"%28r-n%29%2At=c\"   DISABLED_style= \"max-width:90%; height:auto;\" >.<BR>\n" );
document.write( "Solve for r and n.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%28r%2Bn=w%2Ft%2Cr-n=c%2Ft%29 ALIGN=MIDDLE  ALT=\"system%28r%2Bn=w%2Ft%2Cr-n=c%2Ft%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Add corresponding members to Eliminate(Method) n;\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%2Bn%2B%28r-n%29=w%2Ft%2Bc%2Ft ALIGN=MIDDLE  ALT=\"r%2Bn%2B%28r-n%29=w%2Ft%2Bc%2Ft\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%2Br%2Bn-n=%28w%2Bc%29%2Ft ALIGN=MIDDLE  ALT=\"r%2Br%2Bn-n=%28w%2Bc%29%2Ft\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2r=%28w%2Bc%29%2Ft ALIGN=MIDDLE  ALT=\"2r=%28w%2Bc%29%2Ft\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28r=%28w%2Bc%29%2F%282t%29%29 ALIGN=MIDDLE  ALT=\"highlight%28r=%28w%2Bc%29%2F%282t%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.   This is one of the variables solved purely in symbols.\r<BR>\n" );
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document.write( "You can use Elimination again to solve for n.  Seeing that the system has coefficients of 1 on both variables, just subtract corresponding members.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%2Bn-%28r-n%29=w%2Ft-c%2Ft ALIGN=MIDDLE  ALT=\"r%2Bn-%28r-n%29=w%2Ft-c%2Ft\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2n=%28w-c%29%2Ft ALIGN=MIDDLE  ALT=\"2n=%28w-c%29%2Ft\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28n=%28w-c%29%2F%282t%29%29 ALIGN=MIDDLE  ALT=\"highlight%28n=%28w-c%29%2F%282t%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >.  The other variable solved completely in symbolic form.\r<BR>\n" );
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document.write( "This question example uses values assigned to the given variables as<BR>\n" );
document.write( "t=4, w=2060, c=1800.<BR>\n" );
document.write( "Substitute them into the formulas and evaluate. </SPAN>\n" );
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