document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=540816>Question 540816</A>: <I><SPAN STYLE=\"word-break: break-all;\"> An airplane traveled a distance of 400 km at an average speed of x km/h. Write down an expression for the time taken. On the return journey, the speed increased by 40 km/h. Write down an expression for the time for the return journey. If the return journey took 30 minutes less than the outward journey, write down an equation in x and solve it. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #353890 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=353890\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> distance = 400<BR>\n" );
document.write( "speed = x\r<BR>\n" );
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document.write( "t=400/x\r<BR>\n" );
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document.write( "speed increased by 40 on return\r<BR>\n" );
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document.write( "t= 400/(x+40)\r<BR>\n" );
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document.write( "400/x-400/(x+40)=1/2\r<BR>\n" );
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document.write( "Lcd = x(x+40)<BR>\n" );
document.write( "multiply the equation by the LCD\r<BR>\n" );
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document.write( "400(x+40)-400x=x(x+40)/2<BR>\n" );
document.write( "400x+16000-400x=(x^2+40x)/2<BR>\n" );
document.write( "16000=(x^2+40x)/2<BR>\n" );
document.write( "multiply equation by 2<BR>\n" );
document.write( "32000 - x^2+40x<BR>\n" );
document.write( "x^2+40x-32000=0\r<BR>\n" );
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document.write( "x^2+200x-160x-32000=0<BR>\n" );
document.write( "x(x+200)-160(x+200)=0<BR>\n" );
document.write( "(x+200)(x-160)=0<BR>\n" );
document.write( "x= -200 OR 160<BR>\n" );
document.write( "neglect negative value<BR>\n" );
document.write( "The speed = 160 km/h\r<BR>\n" );
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document.write( "m.ananth@hotmail.ca </SPAN>\n" );
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