document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=404881>Question 404881</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a boat takes 2 hours to go 30 km downstream and 3 hours to go the same distance upstream. finds its speed 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 #286126 by </B><A HREF=/tutors/aboutme.mpl?userid=Tatiana_Stebko><B>Tatiana_Stebko(1539)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Tatiana_Stebko><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=Tatiana_Stebko><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=286126\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> If the boat speed is x kmh, river speed is y kmh, then when boat go downsteram it speed is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28x%2By%29 ALIGN=MIDDLE  ALT=\"%28x%2By%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >, upstream speed is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28x-y%29 ALIGN=MIDDLE  ALT=\"%28x-y%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "a boat takes 2 hours to go 30 km downstream, so downstream speed is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=30%2F2=15 ALIGN=MIDDLE  ALT=\"30%2F2=15\"   DISABLED_style= \"max-width:90%; height:auto;\" > kmh, so <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28x%2By%29=15 ALIGN=MIDDLE  ALT=\"%28x%2By%29=15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "a boat takes 3 hours to go 30 km upstream, so upstream speed is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=30%2F3=10 ALIGN=MIDDLE  ALT=\"30%2F3=10\"   DISABLED_style= \"max-width:90%; height:auto;\" >kmh<BR>\n" );
document.write( "so <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28x-y%29=10 ALIGN=MIDDLE  ALT=\"%28x-y%29=10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Equations system<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x%2By=15 ALIGN=MIDDLE  ALT=\"x%2By=15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x-y=10 ALIGN=MIDDLE  ALT=\"x-y=10\"   DISABLED_style= \"max-width:90%; height:auto;\" >Add the first equation to the second<BR>\n" );
document.write( ".<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2x=25 ALIGN=MIDDLE  ALT=\"2x=25\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x=25%2F2 ALIGN=MIDDLE  ALT=\"x=25%2F2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x=12.5 ALIGN=MIDDLE  ALT=\"x=12.5\"   DISABLED_style= \"max-width:90%; height:auto;\" > kmh is the boat speed<BR>\n" );
document.write( "The river speed is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12.5%2By=15 ALIGN=MIDDLE  ALT=\"12.5%2By=15\"   DISABLED_style= \"max-width:90%; height:auto;\" > <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y=15-12.5 ALIGN=MIDDLE  ALT=\"y=15-12.5\"   DISABLED_style= \"max-width:90%; height:auto;\" >  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y=2.5 ALIGN=MIDDLE  ALT=\"y=2.5\"   DISABLED_style= \"max-width:90%; height:auto;\" >kmh<BR>\n" );
document.write( "Answer The boat speed is 12.5 kmh </SPAN>\n" );
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