document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=732118>Question 732118</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a boat travels 2 miles upstream and 2 miles downstream in 5 hours. in still water, the boat travels 2 miles/hour.<BR>\n" );
document.write( "1. what is speed of river's current?<BR>\n" );
document.write( "2. how fast does it travel upstream?<BR>\n" );
document.write( "3. how fast does it travel downstream?<BR>\n" );
document.write( "4. how long does it take to travel downstream?<BR>\n" );
document.write( "5. how long does it take to travel upstream?\r<BR>\n" );
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document.write( "Thank you. Gwen </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #447563 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=447563\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> let current speed = x\r<BR>\n" );
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document.write( "boat speed =2 mph\r<BR>\n" );
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document.write( "against current 2-x<BR>\n" );
document.write( "with current x+2\r<BR>\n" );
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document.write( "2/(x+2)+2/(2-x) = 5\r<BR>\n" );
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document.write( "2(2-x)+2(x+2)=5(4-x^2)\r<BR>\n" );
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document.write( "4-2x+2x+4 = 20-5x^2\r<BR>\n" );
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document.write( "5x^2=12<BR>\n" );
document.write( "x^2= 12/5\r<BR>\n" );
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document.write( "x= sqrt(12/5)\r<BR>\n" );
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document.write( "upstream speed = 2- 1.55= 0.45 mph<BR>\n" );
document.write( "downstream speed = 2+sqrt(12/5)= 3.55 mph\r<BR>\n" );
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document.write( "downstream time = 2/3.55= 0.56 hours<BR>\n" );
document.write( "upstream time = 2/0.45=4.44 <BR>\n" );
document.write( "Total time = 5 hours\r<BR>\n" );
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document.write( " </SPAN>\n" );
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