document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1099109>Question 1099109</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Alvin paddled for 5 hours with a 3&#8203;-km/h current to reach a campsite. The return trip against the same current took 8 hours.\r<BR>\n" );
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document.write( "What is the speed of the boat in still&#8203; water?<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #713510 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=713510\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> rate * time = distance.\r<BR>\n" );
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document.write( "let r = rate and t = time and d = distance\r<BR>\n" );
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document.write( "going downstream, the formula becomes (r+3) * 5 = d<BR>\n" );
document.write( "coming back upstream, the formula becomes (r-3) * 8 = d\r<BR>\n" );
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document.write( "the distance downstream is the same as the distance upstream, so (r+3) * 5 = (r-3) * 8\r<BR>\n" );
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document.write( "simplify to get 5r + 15 = 8r - 24\r<BR>\n" );
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document.write( "subtract 5r from both sides of this equation and add 24 to both sides of this equation to get 39 = 3r\r<BR>\n" );
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document.write( "solve for r to get r = 39/3 = 13\r<BR>\n" );
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document.write( "he paddles at 13 kilometers per hour.\r<BR>\n" );
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document.write( "going downstream, the stream adds 3 kilometers per hours to this to get 16 kilometers per hour for 5 hours = 80 kilometers.\r<BR>\n" );
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document.write( "coming back upstream, the stream subtracts 3 kilometers from this to get 10 kilometers per hour for 8 hours = 80 kilometers.\r<BR>\n" );
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document.write( "the distance downstream and upstream is the same at 80 kilometers.\r<BR>\n" );
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document.write( "the speed of the boat is 13 kilometers per hour </SPAN>\n" );
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