document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=170051>Question 170051</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me with:\r<BR>\n" );
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document.write( "The speed of the current in a river is 2mph.  Jay travels 20 miles upstream and then 20 miles downstream in a total time of 5 1/3 hours.  Find the speed of the boat.\r<BR>\n" );
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document.write( "Let s be the speed of the boat.<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 #125510 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=125510\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The speed of the current in a river is 2mph. Jay travels 20 miles upstream and then 20 miles downstream in a total time of 5 1/3 hours. Find the speed of the boat. <BR>\n" );
document.write( "Let s be the speed of the boat.<BR>\n" );
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document.write( "Upstream DATA:<BR>\n" );
document.write( "distance = 20 miles ; rate = s-2 mph ; time = d/r = 20/(s-2) hrs.<BR>\n" );
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document.write( "Downstream DATA:<BR>\n" );
document.write( "distance = 20 miles ; rate = s+2 mph ; time = d/r = 20(s+2) hrs.<BR>\n" );
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document.write( "EQUATION:<BR>\n" );
document.write( "time + time = 16/3 hrs<BR>\n" );
document.write( "20/(s-2) + 20/(s+2) = 16/3<BR>\n" );
document.write( "60(s+2) + 60(s-2) = 16(s^2 - 4)<BR>\n" );
document.write( "120s = 16s^2 - 64<BR>\n" );
document.write( "16s^2 - 120s - 64 = 0<BR>\n" );
document.write( "2s^2 - 15s - 8 = 0<BR>\n" );
document.write( "s = [15 +- sqrt(225 -4*2*-8)]/4\r<BR>\n" );
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document.write( "s = [15 +- sqrt(289)]/4<BR>\n" );
document.write( "s = [15 +- 17]/4<BR>\n" );
document.write( "Positive solution:<BR>\n" );
document.write( "s = 8 mph (speed of the boat)<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
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