document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=183638>Question 183638</A>This question is from textbook <A HREF=http://www.amazon.com/exec/obidos/ASIN/9780395977224/algebrahomeworkh>Algebra</A><BR>\n" );
document.write( ": <I><SPAN STYLE=\"word-break: break-all;\"> A sailboat travels 20 miles downstream in three hours.  It returns in four hours.  Find the speed of the sailboat in still water AND the rate of the current. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #137877 by </B><A HREF=/tutors/aboutme.mpl?userid=halbren><B>halbren(10)</B></A><img src=\"/images/stars/stars-05.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=halbren><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=137877\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> This is a speed and distance problem. The assumption here is the speed of the sailboat is the same in both direction. The current however will help travel downstream and low travel upstream. The distance travelled in each direction will be the same.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d=s%2At+%2B+c%2At ALIGN=MIDDLE  ALT=\"d=s%2At+%2B+c%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" > where s=speed of sailboat and c=speed of current<BR>\n" );
document.write( "downstream would be<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20+=+s%2A3+%2B+c%2A3 ALIGN=MIDDLE  ALT=\"20+=+s%2A3+%2B+c%2A3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "coming back upstream<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20+=+s%2A4+-+c%2A4 ALIGN=MIDDLE  ALT=\"20+=+s%2A4+-+c%2A4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "If we solve the second equation for s we get<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20+%2B+4c+=+4s ALIGN=MIDDLE  ALT=\"20+%2B+4c+=+4s\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Divide both sides by 4<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20%2F4+%2B+4c%2F4+=+4s%2F4 ALIGN=MIDDLE  ALT=\"20%2F4+%2B+4c%2F4+=+4s%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Simplify<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5%2Bc=s ALIGN=MIDDLE  ALT=\"5%2Bc=s\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Using substitution, replace s with 5+c in first equation<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20+=+3%285%2Bc%29%2B3c ALIGN=MIDDLE  ALT=\"20+=+3%285%2Bc%29%2B3c\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Distribute to remove parenthesis<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20=15%2B3c%2B3c ALIGN=MIDDLE  ALT=\"20=15%2B3c%2B3c\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Move constants to one side and combined like variables<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=20-15=6c ALIGN=MIDDLE  ALT=\"20-15=6c\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5=6c ALIGN=MIDDLE  ALT=\"5=6c\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "divide both sides by 6<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5%2F6=6c%2F6 ALIGN=MIDDLE  ALT=\"5%2F6=6c%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=c=5%2F6 ALIGN=MIDDLE  ALT=\"c=5%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" >mph<BR>\n" );
document.write( "Put this value for c back into s=5+c<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=s=5%2B5%2F6 ALIGN=MIDDLE  ALT=\"s=5%2B5%2F6\"   DISABLED_style= \"max-width:90%; height:auto;\" >mph </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );