document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=106198>Question 106198</A>: <I><SPAN STYLE=\"word-break: break-all;\"> On a river a boat travels 240 miles downstream in the same amount of time that it takes to travel 160 miles upstream.  The speed of the boat without current is 25 mph.  Find the speed of the river.  Be sure to define your variable, write an equation, and show how you solved it. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #77326 by </B><A HREF=/tutors/aboutme.mpl?userid=ptaylor><B>ptaylor(2198)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ptaylor><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=ptaylor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=77326\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <BR>\n" );
document.write( "distance(d) equals rate(r) times time(t) or d=rt; r=d/t and t=d/r\r<BR>\n" );
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document.write( "Let r=speed (rate) of the river\r<BR>\n" );
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document.write( "rate of the boat downstream=25+r<BR>\n" );
document.write( "rate of the boat upstream=25-r\r<BR>\n" );
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document.write( "Time to travel downstream=(distance downstream)/(rate downstream)=240/(25+r)<BR>\n" );
document.write( "Time to travel upstream=(distance upstream)/(rate upstream)=160/(25-r)\r<BR>\n" );
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document.write( "Now we are told that these two times are equal. So:\r<BR>\n" );
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document.write( "240/(25+r)=160/(25-r)  multiply both sides by (25+r)(25-r)\r<BR>\n" );
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document.write( "240(25-r)=160(25+r)  get rid of parens<BR>\n" );
document.write( "6000-240r=4000+160r  subtract 6000 and also 160r from both sides\r<BR>\n" );
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document.write( "6000-6000-240r-160r=4000-6000+160r-160r  collect like terms\r<BR>\n" );
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document.write( "-400r=-2000  divide both sides by -400\r<BR>\n" );
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document.write( "r=5 mph-------------------rate (speed) of the river\r<BR>\n" );
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document.write( "CK<BR>\n" );
document.write( "240/30=160/20<BR>\n" );
document.write( "8=8\r<BR>\n" );
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document.write( "Hope this helps---ptaylor<BR>\n" );
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