document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=307439>Question 307439</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A jet plane flying with the wind flew 2400 miles in 4 hours. Against the wind, the plane flew only 2000 miles in 4 hours. 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 #219949 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=219949\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A jet plane flying with the wind flew 2400 miles in 4 hours. Against the wind, the plane flew only 2000 miles in 4 hours. Find the rate of the plane in calm air and the rate of the wind.\r<BR>\n" );
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document.write( "let the the rate of plane instill air be x mph<BR>\n" );
document.write( "& the rate of wind be y mph<BR>\n" );
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document.write( "with wind the rate will be x+y mph\r<BR>\n" );
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document.write( "Against wind the rate will be x-y mph<BR>\n" );
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document.write( "Time taken with wind will be 2400 / x+y......  ( time = distance / rate)<BR>\n" );
document.write( "Time taken against wind will be 2000/ x-y<BR>\n" );
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document.write( "2400 /x+y = 4\r<BR>\n" );
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document.write( "2000/ x-y =4\r<BR>\n" );
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document.write( "4(x+y)=2400<BR>\n" );
document.write( "4(x-y)=2000<BR>\n" );
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document.write( "4x+4y=2400<BR>\n" );
document.write( "4x-4y=2000<BR>\n" );
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document.write( "Add the two equations<BR>\n" );
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document.write( "4x+4y+4x-4y= 4400\r<BR>\n" );
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document.write( "8x= 4400<BR>\n" );
document.write( "x= 550 mph the rate of the plane<BR>\n" );
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document.write( "4x+4y=2400<BR>\n" );
document.write( "plug the value of x \r<BR>\n" );
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document.write( "4*550+4y= 2400\r<BR>\n" );
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document.write( "2200 +4y= 2400<BR>\n" );
document.write( "4y= 2400-2200\r<BR>\n" );
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document.write( "4y=200\r<BR>\n" );
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document.write( "y=50 mph the rate of the wind<BR>\n" );
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document.write( ".\r<BR>\n" );
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document.write( "Ananth\r<BR>\n" );
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document.write( "  </SPAN>\n" );
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