document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=23139>Question 23139</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a boat takes 2 hours longer to go 45 miles up a river than to return. If the boat's speed in still water is 12 mph, what is the rate of the current.<BR>\n" );
document.write( "Can you please show you step this time. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #11607 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon%21><B>stanbon!(97)</B></A><img src=\"/images/stars/stars-08.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon%21><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=11607\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Downstream Data: distance= 45; rate=12+c; time=45/(12+c)<BR>\n" );
document.write( "Upstream Data: distance = 45: rate = 12-c; time= 45/(12-c)<BR>\n" );
document.write( "EQUATION:<BR>\n" );
document.write( "Time Upstream - Time Downstream = 2 hours<BR>\n" );
document.write( "   45/(12-c) - 45/(12+c) = 2<BR>\n" );
document.write( "Divide thru by 45 to get:<BR>\n" );
document.write( "    1/(12-c) - 1/(12-c) =2/45<BR>\n" );
document.write( "Simplify :<BR>\n" );
document.write( "   45[(12+c)-(12-c)]= 2[(12-c)(12+c)]<BR>\n" );
document.write( "   45[2c] =2[144-c^2]<BR>\n" );
document.write( "   90c = 288-2c^2<BR>\n" );
document.write( "   c^2+45c-144=0<BR>\n" );
document.write( "   (c-3)(c+48)=0<BR>\n" );
document.write( "   current speed = 3 mph\r<BR>\n" );
document.write( "\n" );
document.write( "Cheers,<BR>\n" );
document.write( "Stan H. </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );