document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=439228>Question 439228</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In a 16 km cross-country ski race Brett skied the first 7 km at a constant speed and then increased his speed by 3 km/h for the last 9 km.  If he finished the entire race in 1 hour and 20 minutes, what was his speed for the first 7 km?\r<BR>\n" );
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document.write( "my teacher gave me the answer 10.5 km/hr but i cant set it up right. i know that d = r X t but for some reason when i set up the problem i get a different answer everytime and its never the right one. thanks for your help! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #303541 by </B><A HREF=/tutors/aboutme.mpl?userid=jorel1380><B>jorel1380(3719)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jorel1380><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=jorel1380><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=303541\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 7/x+9/(x+3)=1 1/3<BR>\n" );
document.write( "7/x+9/(x+3)=4/3 hrs.<BR>\n" );
document.write( "Multiply all by 3(x)(x+3):<BR>\n" );
document.write( "7x3x(x+3)+9x3xX=4(x)(x+3)<BR>\n" );
document.write( "21x+63+27x=4x2+12x<BR>\n" );
document.write( "0=4x2-36x-63<BR>\n" );
document.write( "0=(2x+3)(2x-21)<BR>\n" );
document.write( "x=-3/2 or 21/2<BR>\n" );
document.write( "Throwing out the negative answer, we get Brett's initial speed to be 10.5 kph.  Your teacher is actually right!!!!! </SPAN>\n" );
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