document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=204081>Question 204081</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Can someone help me solve this word problem?\r<BR>\n" );
document.write( "\n" );
document.write( "The Hudson River flows at a rate of 5 miles per hour.  A patrol boat travels 40 miles upriver, and returns in a total time of 6 hrs.  What is the speed of the boat 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 #154026 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=154026\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The Hudson River flows at a rate of 5 miles per hour. A patrol boat travels 40 miles upriver, and returns in a total time of 6 hrs. What is the speed of the boat in still water?<BR>\n" );
document.write( "--------------------------<BR>\n" );
document.write( "Upriver DATA:<BR>\n" );
document.write( "distance = 40 miles ; rate = b-5 ; time = d/r = 40/(b-5) hrs.<BR>\n" );
document.write( "--------------------------<BR>\n" );
document.write( "Downriver DATA:<BR>\n" );
document.write( "distance = 40 miles ; rate = b+5 ; time = 40/(b+5) hrs<BR>\n" );
document.write( "---------------------------<BR>\n" );
document.write( "Equation:<BR>\n" );
document.write( "time up + time down = 6 hrs<BR>\n" );
document.write( "---<BR>\n" );
document.write( "40/(b-5) + 40/(b+5) = 6<BR>\n" );
document.write( "---<BR>\n" );
document.write( "Multiply thru by (b-5)(b+5) to get:<BR>\n" );
document.write( "40(b+5) + 40(b-5) = 6(b^2-25)<BR>\n" );
document.write( "80b = 6b^2 - 150<BR>\n" );
document.write( "6b^2 - 80b - 150 = 0<BR>\n" );
document.write( "3b^2 - 40b - 75 = 0<BR>\n" );
document.write( "(b-15)(3b+5) = 0<BR>\n" );
document.write( "Positive solution:<BR>\n" );
document.write( "b = 15 mph (speed of the boat in still water)<BR>\n" );
document.write( "===============================================<BR>\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );