document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=290001>Question 290001</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A barge travels 63 miles upriver and 63 miles downriver in a toal time of 15 hours. the speed of the current is 4 mph. Find the speed of the barge 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 #209925 by </B><A HREF=/tutors/aboutme.mpl?userid=Fombitz><B>Fombitz(32388)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Fombitz><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/cgi-bin/show-face.mpl?user=Fombitz><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=209925\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Rate*Time=Distance<BR>\n" );
document.write( "Let's call the speed of the barge S. <BR>\n" );
document.write( "Against the current,<BR>\n" );
document.write( "1.<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28S-4%29%2AT1=63 ALIGN=MIDDLE  ALT=\"%28S-4%29%2AT1=63\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "With the current,<BR>\n" );
document.write( "2.<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28S%2B4%29%2AT2=63 ALIGN=MIDDLE  ALT=\"%28S%2B4%29%2AT2=63\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and we also know<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=T1%2BT2=15 ALIGN=MIDDLE  ALT=\"T1%2BT2=15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "From eq. 1 and 2,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=T1=63%2F%28S-4%29 ALIGN=MIDDLE  ALT=\"T1=63%2F%28S-4%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=T2=63%2F%28S%2B4%29 ALIGN=MIDDLE  ALT=\"T2=63%2F%28S%2B4%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Then,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=63%2F%28S-4%29%2B63%2F%28S%2B4%29=15 ALIGN=MIDDLE  ALT=\"63%2F%28S-4%29%2B63%2F%28S%2B4%29=15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=63%28S%2B4%29%2B63%28S-4%29=15%28S%2B4%29%28S-4%29 ALIGN=MIDDLE  ALT=\"63%28S%2B4%29%2B63%28S-4%29=15%28S%2B4%29%28S-4%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=63S%2B252%2B63S-252=15%28S%5E2-4S%2B4S-16%29 ALIGN=MIDDLE  ALT=\"63S%2B252%2B63S-252=15%28S%5E2-4S%2B4S-16%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=126S=15S%5E2-240 ALIGN=MIDDLE  ALT=\"126S=15S%5E2-240\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=15S%5E2-126S-240=0 ALIGN=MIDDLE  ALT=\"15S%5E2-126S-240=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5S%5E2-42S-80=0 ALIGN=MIDDLE  ALT=\"5S%5E2-42S-80=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "You can factor this equation.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%285S%2B8%29%28S-10%29=0 ALIGN=MIDDLE  ALT=\"%285S%2B8%29%28S-10%29=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Two solutions,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5S%2B8=0 ALIGN=MIDDLE  ALT=\"5S%2B8=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5S=-8 ALIGN=MIDDLE  ALT=\"5S=-8\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S=-8%2F5 ALIGN=MIDDLE  ALT=\"S=-8%2F5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S-10=0 ALIGN=MIDDLE  ALT=\"S-10=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=S=10 ALIGN=MIDDLE  ALT=\"S=10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Since we specified the direction of with and against the current, we assumed the barge speed was positive, so we only keep the positive result.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28S=10%29 ALIGN=MIDDLE  ALT=\"highlight%28S=10%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );