document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=311941>Question 311941</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Horizons have a manufacturing plant located 300 mi from company headquarters. Their corporate pilot must fly from headquarters to the plant and back in 4 hrs. If there is a 20-mph headwind going and a 20-mph headwind tailwind returning, how fast must the plane be able to travel in still air? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #223071 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=223071\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 300/x+20 + 300 / x-20 = 4\r<BR>\n" );
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document.write( "LCM (x+20)(x-20)<BR>\n" );
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document.write( "300(x-20)+300(x+20)= 4x^2-1600<BR>\n" );
document.write( "300x-6000 +300x+6000= 4x^2-1600<BR>\n" );
document.write( "4x^2-600x-1600=0<BR>\n" );
document.write( "x^2-150x-400=0<BR>\n" );
document.write( "Find X1 , X2 the roots of the equation\r<BR>\n" );
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document.write( "X1= 150+sqrt((-150)^2+1600) / 2\r<BR>\n" );
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document.write( "x= 152.6 mph </SPAN>\n" );
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