document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1010958>Question 1010958</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Hi,\r<BR>\n" );
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document.write( "Thank you for answering my question in advance.\r<BR>\n" );
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document.write( "A trucker calculates that if he increased his average speed by 20 km/hr, he could travel his 800 km route in 2.0 hours less time than usual. Find his usual speed. \r<BR>\n" );
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document.write( "Thank you </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #626460 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39617)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><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=626460\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%28r=unknownUsualSpeed%2Ct=unknownUsualTime%2Ch=2%2Ck=20%2Cd=800%29 ALIGN=MIDDLE  ALT=\"system%28r=unknownUsualSpeed%2Ct=unknownUsualTime%2Ch=2%2Ck=20%2Cd=800%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<PRE STYLE=\"white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;\">\r\n" );
document.write( "          rate      time       distance\r\n" );
document.write( "IF        r+k       t-h         d\r\n" );
document.write( "USUAL     r          t          d\r\n" );
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document.write( "System of equations to solve for t and r:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%28%28r%2Bk%29%28t-h%29=d%2Crt=d%29 ALIGN=MIDDLE  ALT=\"system%28%28r%2Bk%29%28t-h%29=d%2Crt=d%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "STEPS FOR SOLVING - ARITHMETIC<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=rt%2Bkt-hr-kh=d ALIGN=MIDDLE  ALT=\"rt%2Bkt-hr-kh=d\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "substitute for d using \"usual\" equation;<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=rt%2Bkt-hr-kh=rt ALIGN=MIDDLE  ALT=\"rt%2Bkt-hr-kh=rt\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=kt-hr-kh=0 ALIGN=MIDDLE  ALT=\"kt-hr-kh=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t=%28hr%2Bkh%29%2Fk ALIGN=MIDDLE  ALT=\"t=%28hr%2Bkh%29%2Fk\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Again use the \"usual\" equation, now substituting for t.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%28hr%2Bkh%29%2Fk=d ALIGN=MIDDLE  ALT=\"r%28hr%2Bkh%29%2Fk=d\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%28hr%2Bkh%29=kd ALIGN=MIDDLE  ALT=\"r%28hr%2Bkh%29=kd\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=hr%5E2%2Bkhr=kd ALIGN=MIDDLE  ALT=\"hr%5E2%2Bkhr=kd\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%28hr%5E2%2Bkhr-kd=0%29 ALIGN=MIDDLE  ALT=\"highlight_green%28hr%5E2%2Bkhr-kd=0%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >------almost to a formula for r.   You can decide when you want to <BR>\n" );
document.write( "make the substitutions for the given values.  Continue symbolically from here and substitute later,<BR>\n" );
document.write( "or do the substitutions now, and continue the arithmetic either way.<BR>\n" );
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document.write( "Substituting now,  and get<BR>\n" );
document.write( "after simplifying,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5E2%2B20r-8000=0 ALIGN=MIDDLE  ALT=\"r%5E2%2B20r-8000=0\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Formula for general solution of quadratic equation gives <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28r=80%29 ALIGN=MIDDLE  ALT=\"highlight%28r=80%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >. </SPAN>\n" );
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