document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=696737>Question 696737</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A boat can travel with a speed of 15 km/hr in still water. it needs 4 more hours to travel 63km agains the current of a river than it needs to travel down the river find the speed of the river<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #429274 by </B><A HREF=/tutors/aboutme.mpl?userid=josmiceli><B>josmiceli(19441)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josmiceli><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=josmiceli><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=429274\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+ ALIGN=MIDDLE  ALT=\"+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the boat's time in hrs to travel 63 km downstream<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+ ALIGN=MIDDLE  ALT=\"+c+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = the speed of the current in km/hr<BR>\n" );
document.write( "The boat's speed going downstream is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+15+%2B+c+ ALIGN=MIDDLE  ALT=\"+15+%2B+c+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The boat's speed going upstream is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+15+-+c+ ALIGN=MIDDLE  ALT=\"+15+-+c+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "------------<BR>\n" );
document.write( "given:<BR>\n" );
document.write( "Equation for going upstream is<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+63+=+%28+15+-+c+%29%2A%28+t+%2B+4+%29+ ALIGN=MIDDLE  ALT=\"+63+=+%28+15+-+c+%29%2A%28+t+%2B+4+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Equation for going downstream is<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+63+=+%28+15+%2B+c+%29%2At+ ALIGN=MIDDLE  ALT=\"+63+=+%28+15+%2B+c+%29%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "----------------------<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+63+=+15t+-+c%2At+%2B+60+-+4c+ ALIGN=MIDDLE  ALT=\"+63+=+15t+-+c%2At+%2B+60+-+4c+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+15t+-+c%2At+=+3+%2B+4c+ ALIGN=MIDDLE  ALT=\"+15t+-+c%2At+=+3+%2B+4c+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t%2A%28+15+-+c+%29+=+3+%2B+4c+ ALIGN=MIDDLE  ALT=\"+t%2A%28+15+-+c+%29+=+3+%2B+4c+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+3+%2B+4c+%29+%2F+%28+15+-+c+%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+3+%2B+4c+%29+%2F+%28+15+-+c+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "----------------------------<BR>\n" );
document.write( "Substitute (1) into (2)<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+63+=+%28+15+%2B+c+%29%2A%28+3+%2B+4c+%29+%2F+%28+15+-+c+%29++ ALIGN=MIDDLE  ALT=\"+63+=+%28+15+%2B+c+%29%2A%28+3+%2B+4c+%29+%2F+%28+15+-+c+%29++\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+63%2A%28+15+-+c+%29+=++%28+15+%2B+c+%29%2A%28+3+%2B+4c+%29+ ALIGN=MIDDLE  ALT=\"+63%2A%28+15+-+c+%29+=++%28+15+%2B+c+%29%2A%28+3+%2B+4c+%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+945+-+63c+=+45+%2B+3c+%2B+60c+-+4c%5E2+ ALIGN=MIDDLE  ALT=\"+945+-+63c+=+45+%2B+3c+%2B+60c+-+4c%5E2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+4c%5E2+-+126c+%2B+900+=+0+ ALIGN=MIDDLE  ALT=\"+4c%5E2+-+126c+%2B+900+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+2c%5E2+-+63c+%2B+450+=+0+ ALIGN=MIDDLE  ALT=\"+2c%5E2+-+63c+%2B+450+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Use quadratic equation:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"+c+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+a+=+2+ ALIGN=MIDDLE  ALT=\"+a+=+2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+-63+ ALIGN=MIDDLE  ALT=\"+b+=+-63+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+450+ ALIGN=MIDDLE  ALT=\"+c+=+450+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+%28-%28-63%29+%2B-+sqrt%28+%28-63%29%5E2-4%2A2%2A450+%29%29%2F%282%2A2%29+ ALIGN=MIDDLE  ALT=\"+c+=+%28-%28-63%29+%2B-+sqrt%28+%28-63%29%5E2-4%2A2%2A450+%29%29%2F%282%2A2%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+%28+63+%2B-+sqrt%28+3969+-+3600+%29%29%2F4+ ALIGN=MIDDLE  ALT=\"+c+=+%28+63+%2B-+sqrt%28+3969+-+3600+%29%29%2F4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+%28+63+%2B-+sqrt%28+369+%29%29%2F4+ ALIGN=MIDDLE  ALT=\"+c+=+%28+63+%2B-+sqrt%28+369+%29%29%2F4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+%28+63+%2B-+sqrt%28+369+%29%29%2F4+ ALIGN=MIDDLE  ALT=\"+c+=+%28+63+%2B-+sqrt%28+369+%29%29%2F4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "You'll have to finish, but this is the basic idea<BR>\n" );
document.write( "of how to solve. Then check the work.\r<BR>\n" );
document.write( "\n" );
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