document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=202323>Question 202323</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/9780073533490/algebrahomeworkh>Elementary and Intermediate Algebra</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> Gone fishing. Debbie traveled by boat 5 miles upstream to<BR>\n" );
document.write( "fish in her favorite spot. Because of the 4-mph current, it<BR>\n" );
document.write( "took her 20 minutes longer to get there than to return. How<BR>\n" );
document.write( "fast will her boat go in still water? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #152557 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=152557\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Debbie traveled by boat 5 miles upstream to<BR>\n" );
document.write( "fish in her favorite spot. Because of the 4-mph current, it<BR>\n" );
document.write( "took her 20 minutes longer to get there than to return. How<BR>\n" );
document.write( "fast will her boat go in still water?<BR>\n" );
document.write( "-----------------------<BR>\n" );
document.write( "Upstream DATA:<BR>\n" );
document.write( "distance = 5 miles; time = x + 20  ; rate = d/t = 5/(x+2) hrs.<BR>\n" );
document.write( "---------------------------<BR>\n" );
document.write( "Downstream DATA:<BR>\n" );
document.write( "distance = 5 miles ; time = x ; rate = d/t = 5/x<BR>\n" );
document.write( "----------------------------<BR>\n" );
document.write( "Equation:<BR>\n" );
document.write( "rate upstream = b-4=5/(x+2)<BR>\n" );
document.write( "rate downstrea= b+4=5/x<BR>\n" );
document.write( "--------------------------<BR>\n" );
document.write( "Subtract 1st from 2nd to get:<BR>\n" );
document.write( "8 = 5/x - 5/(x+2)<BR>\n" );
document.write( "Solve for \"x\":<BR>\n" );
document.write( " 8x(x+2) = 5(x+2) - 5x<BR>\n" );
document.write( "8x^2+16x = 10<BR>\n" );
document.write( "4x^2+8x-5 = 0<BR>\n" );
document.write( "4x^2+10x-2x-5 = 0<BR>\n" );
document.write( "2x(2x+5)-(2x+5) = 0<BR>\n" );
document.write( "(2x+5)(2x-1) = 0<BR>\n" );
document.write( "Positive solution:<BR>\n" );
document.write( "x = 1/2<BR>\n" );
document.write( "---------------------<BR>\n" );
document.write( "Solve for \"b\" when b+4 = 5/x<BR>\n" );
document.write( "b+4 = 5/(1/2)<BR>\n" );
document.write( "b+4 = 10<BR>\n" );
document.write( "b = 6 mph (speed of the boat in still water)<BR>\n" );
document.write( "=================================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H.\r<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );