document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1207221>Question 1207221</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A motorboat travels the distance from one pier to another pier in 4 hours and the way back in 5 hours. What is the speed of the boat in still water if it travels 70 km with the current in 3.5 hours? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #844967 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39620)</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=844967\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <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( "               SPEED          TIME       DISTANCE(kilometers)\r\n" );
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document.write( "GOING TO         r+c            4           d\r\n" );
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document.write( "RETURNING        r-c            5           d\r\n" );
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document.write( "condition        r+c            3.5          70\r\n" );
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document.write( "r, speed of boat without current<BR>\n" );
document.write( "c, speed of the current\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%284%28r%2Bc%29=5%28r-c%29%2Cr%2Bc=70%2F3.5%29 ALIGN=MIDDLE  ALT=\"system%284%28r%2Bc%29=5%28r-c%29%2Cr%2Bc=70%2F3.5%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "See a very obvious substitution, for r+c.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%284%2870%2F3.5%29=5r-5c%2Cr%2Bc=70%2F3.5%29 ALIGN=MIDDLE  ALT=\"system%284%2870%2F3.5%29=5r-5c%2Cr%2Bc=70%2F3.5%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Simpler,  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%285r-5c=80%2Cr%2Bc=20%29 ALIGN=MIDDLE  ALT=\"system%285r-5c=80%2Cr%2Bc=20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Even still simpler<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=system%28r-c=16%2Cr%2Bc=20%29 ALIGN=MIDDLE  ALT=\"system%28r-c=16%2Cr%2Bc=20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
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