document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=839167>Question 839167</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A cyclist travels a distance of 120km from Town A to Town B at an average speed of x km/h. If he increases his speed by 1km/h, he would save 30 minutes. Find x </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #505596 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=505596\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A cyclist travels a distance of 120km from Town A to Town B at an average speed of x km/h. If he increases his speed by 1km/h, he would save 30 minutes. Find x\r<BR>\n" );
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document.write( "Original Time - time after speed increase = 1/2 hour\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=120%2Fx+-+120%2F%28x%2B1%29+=+1%2F2 ALIGN=MIDDLE  ALT=\"120%2Fx+-+120%2F%28x%2B1%29+=+1%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "multiply the equation by 2x(x+1)\r<BR>\n" );
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document.write( "we get\r<BR>\n" );
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document.write( "2*120(x+1) -2*120*x = x(x+1)\r<BR>\n" );
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document.write( "240x+240 -240x=x^2+x\r<BR>\n" );
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document.write( "x^2+x-240=0\r<BR>\n" );
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document.write( "x^2+16x-15x-240=0\r<BR>\n" );
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document.write( "x(x+16)-15(x+16)=0\r<BR>\n" );
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document.write( "(x+16)(x-15)=0\r<BR>\n" );
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document.write( "x cannot be negative<BR>\n" );
document.write( "so x=15 </SPAN>\n" );
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