document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=451949>Question 451949</A>: <I><SPAN STYLE=\"word-break: break-all;\"> At a high school cross country meet, Jared jogged 8 mph for the first part of the race, then increased his speed to 12 mph for the second part. If the race was 21 mi. long and Jared finished in 2hr., how far did he jog the faster pace </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #310721 by </B><A HREF=/tutors/aboutme.mpl?userid=pedjajov><B>pedjajov(51)</B></A><img src=\"/images/stars/stars-08.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=pedjajov><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=310721\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Jared ran a distance d=12mi that consists of two parts d1 and d2 -> d=d1+d2.\r<BR>\n" );
document.write( "\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d1=8%2At1 ALIGN=MIDDLE  ALT=\"d1=8%2At1\"   DISABLED_style= \"max-width:90%; height:auto;\" > , he ran  8mi/h for t1 hours<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d2=12%2At2 ALIGN=MIDDLE  ALT=\"d2=12%2At2\"   DISABLED_style= \"max-width:90%; height:auto;\" >, he ran 12mi/h for t2 hours\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "8*t1+12*t2 = 21\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "Since he finished his race in 2 hours it means \r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "t1 + t2 = 2, from here we have t1=2-t2\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "If we substitute this into first equation we have:\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "8(2-t2)+12*t2=21, multiply<BR>\n" );
document.write( "16-8*t2+12*t2=21, combine<BR>\n" );
document.write( "16-4*t2      =21, subtract 16 from both sides<BR>\n" );
document.write( "-4*t2        =-5, divide both sides by -4<BR>\n" );
document.write( "   t2        = 5/4\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( "So he ran faster for 5/4 hours or 75 minutes.\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );