document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=880014>Question 880014</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a boat goes 16 km upstream and 24 km downstream in 6 hours. it also covers 12 km  upstream and 36 km downstream in same time. find the rate of speed still in water and stream. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #531234 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=531234\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a boat goes 16 km upstream and 24 km downstream in 6 hours.<BR>\n" );
document.write( " it also covers 12 km upstream and 36 km downstream in same time.<BR>\n" );
document.write( " find the rate of speed still in water and stream.<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Let s = rate of speed in still water<BR>\n" );
document.write( "let c = rate of the current<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(s-c) = effective speed upstream<BR>\n" );
document.write( "and<BR>\n" );
document.write( "(s+c) = effective speed downstream<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Write a time equation for each trip, time = dist/speed<BR>\n" );
document.write( ":<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=16%2F%28%28s-c%29%29 ALIGN=MIDDLE  ALT=\"16%2F%28%28s-c%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=24%2F%28%28s%2Bc%29%29 ALIGN=MIDDLE  ALT=\"24%2F%28%28s%2Bc%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 6<BR>\n" );
document.write( "and<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12%2F%28%28s-c%29%29 ALIGN=MIDDLE  ALT=\"12%2F%28%28s-c%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=36%2F%28%28s%2Bc%29%29 ALIGN=MIDDLE  ALT=\"36%2F%28%28s%2Bc%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 6<BR>\n" );
document.write( "Simplify both equations, divide the 1st by 2, the 2nd by 3 and we have<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=8%2F%28%28s-c%29%29 ALIGN=MIDDLE  ALT=\"8%2F%28%28s-c%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12%2F%28%28s%2Bc%29%29 ALIGN=MIDDLE  ALT=\"12%2F%28%28s%2Bc%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 3<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4%2F%28%28s-c%29%29 ALIGN=MIDDLE  ALT=\"4%2F%28%28s-c%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12%2F%28%28s%2Bc%29%29 ALIGN=MIDDLE  ALT=\"12%2F%28%28s%2Bc%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 2<BR>\n" );
document.write( "----------------------------------------Subtraction eliminates (s+c)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4%2F%28%28s-c%29%29 ALIGN=MIDDLE  ALT=\"4%2F%28%28s-c%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + 0 = 1<BR>\n" );
document.write( "4 = s - c<BR>\n" );
document.write( "(c+4) = s<BR>\n" );
document.write( "Using the first original equation replace s with (c+4)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=16%2F%28%28%28c%2B4%29-c%29%29 ALIGN=MIDDLE  ALT=\"16%2F%28%28%28c%2B4%29-c%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=24%2F%28%28%28c%2B4%29%2Bc%29%29 ALIGN=MIDDLE  ALT=\"24%2F%28%28%28c%2B4%29%2Bc%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 6<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=16%2F4 ALIGN=MIDDLE  ALT=\"16%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=24%2F%28%282c%2B4%29%29 ALIGN=MIDDLE  ALT=\"24%2F%28%282c%2B4%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 6<BR>\n" );
document.write( "4 + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=24%2F%28%282c%2B4%29%29 ALIGN=MIDDLE  ALT=\"24%2F%28%282c%2B4%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 6<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=24%2F%28%282c%2B4%29%29 ALIGN=MIDDLE  ALT=\"24%2F%28%282c%2B4%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 6 - 4<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=24%2F%28%282c%2B4%29%29 ALIGN=MIDDLE  ALT=\"24%2F%28%282c%2B4%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 2<BR>\n" );
document.write( "24 = 2(2c + 4)<BR>\n" );
document.write( "24 = 4c + 8<BR>\n" );
document.write( "24 - 8 = 4c<BR>\n" );
document.write( "c = 16/4<BR>\n" );
document.write( "c = 4 mph is the rate of the stream<BR>\n" );
document.write( "and<BR>\n" );
document.write( "s = c+4<BR>\n" );
document.write( "s = 4 + 4<BR>\n" );
document.write( "s = 8 mph is the rate in still water\r<BR>\n" );
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document.write( ":<BR>\n" );
document.write( ":<BR>\n" );
document.write( "See if that checks out in the 2nd equation<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12%2F4%29 ALIGN=MIDDLE  ALT=\"12%2F4%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=36%2F12 ALIGN=MIDDLE  ALT=\"36%2F12\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 6<BR>\n" );
document.write( "3 + 3 = 6<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );