document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=940709>Question 940709</A>: <I><SPAN STYLE=\"word-break: break-all;\"> In still water, Mo and Sally can paddle a canoe at 12 mph. It takes them a total of 6 hours to paddle 32 miles up a river and then return the same distance to their starting point. What is the rate of the current?<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #573319 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=573319\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+12+ ALIGN=MIDDLE  ALT=\"+12+\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi/hr is their speed in still water<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 mi/hr<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+12+%2B+c+ ALIGN=MIDDLE  ALT=\"+12+%2B+c+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = their speed in mi/hr  going downriver<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+12+-+c+ ALIGN=MIDDLE  ALT=\"+12+-+c+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = their speed in mi/hr  going upriver<BR>\n" );
document.write( "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;\" > = their time in hours to go upriver<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+6+-+t+ ALIGN=MIDDLE  ALT=\"+6+-+t+\"   DISABLED_style= \"max-width:90%; height:auto;\" > = their time in hours to go downriver<BR>\n" );
document.write( "------------------------------------------<BR>\n" );
document.write( "Equation for going upriver:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+32+=+%28+12+-+c+%29%2At+ ALIGN=MIDDLE  ALT=\"+32+=+%28+12+-+c+%29%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Equation for going downriver:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+32+=+%28+12+%2B+c+%29%2A%28+6+-+t+%29+ ALIGN=MIDDLE  ALT=\"+32+=+%28+12+%2B+c+%29%2A%28+6+-+t+%29+\"   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=+32+=+12t+-+c%2At+ ALIGN=MIDDLE  ALT=\"+32+=+12t+-+c%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c%2At+=+12t+-+32+ ALIGN=MIDDLE  ALT=\"+c%2At+=+12t+-+32+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+12+-+32%2Ft+ ALIGN=MIDDLE  ALT=\"+c+=+12+-+32%2Ft+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "and<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+32+=+72+%2B+6c+-+12t+-+c%2At+ ALIGN=MIDDLE  ALT=\"+32+=+72+%2B+6c+-+12t+-+c%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+40+=+12t+-+6c+%2B+c%2At+ ALIGN=MIDDLE  ALT=\"+40+=+12t+-+6c+%2B+c%2At+\"   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=+40+=+12t+-+6%2A%28+12+-+32%2Ft+%29+%2B+%28+12+-+32%2Ft+%29%2At+ ALIGN=MIDDLE  ALT=\"+40+=+12t+-+6%2A%28+12+-+32%2Ft+%29+%2B+%28+12+-+32%2Ft+%29%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+40+=+12t+-+72+%2B+192%2Ft+%2B+12t+-+32+ ALIGN=MIDDLE  ALT=\"+40+=+12t+-+72+%2B+192%2Ft+%2B+12t+-+32+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+144+=+192%2Ft+%2B+24t+ ALIGN=MIDDLE  ALT=\"+144+=+192%2Ft+%2B+24t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+18+=+24%2Ft+%2B+3t+ ALIGN=MIDDLE  ALT=\"+18+=+24%2Ft+%2B+3t+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+18t+=+24+%2B+3t%5E2+ ALIGN=MIDDLE  ALT=\"+18t+=+24+%2B+3t%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=+3t%5E2+-+18t+%2B+24+=+0+ ALIGN=MIDDLE  ALT=\"+3t%5E2+-+18t+%2B+24+=+0+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Use the quadratic formula<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+-b+%2B-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"+t+=+%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+=+3+ ALIGN=MIDDLE  ALT=\"+a+=+3+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+b+=+-18+ ALIGN=MIDDLE  ALT=\"+b+=+-18+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+24+ ALIGN=MIDDLE  ALT=\"+c+=+24+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+-%28-18%29+%2B-+sqrt%28+%28-18%29%5E2+-+4%2A3%2A24+%29%29+%2F+%282%2A3%29+ ALIGN=MIDDLE  ALT=\"+t+=+%28+-%28-18%29+%2B-+sqrt%28+%28-18%29%5E2+-+4%2A3%2A24+%29%29+%2F+%282%2A3%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+18+%2B-+sqrt%28+324+-+288+%29%29+%2F+6+ ALIGN=MIDDLE  ALT=\"+t+=+%28+18+%2B-+sqrt%28+324+-+288+%29%29+%2F+6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+18+%2B-+sqrt%28+36+%29%29+%2F+6+ ALIGN=MIDDLE  ALT=\"+t+=+%28+18+%2B-+sqrt%28+36+%29%29+%2F+6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+%28+18+%2B+6+%29+%2F+6+ ALIGN=MIDDLE  ALT=\"+t+=+%28+18+%2B+6+%29+%2F+6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+24%2F6+ ALIGN=MIDDLE  ALT=\"+t+=+24%2F6+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+t+=+4+ ALIGN=MIDDLE  ALT=\"+t+=+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" > hrs ( I picked the right square root because<BR>\n" );
document.write( "the trip upriver should take longer than downriver )<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+6+-+t+=+6+-+4+ ALIGN=MIDDLE  ALT=\"+6+-+t+=+6+-+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+6+-+t+=+2+ ALIGN=MIDDLE  ALT=\"+6+-+t+=+2+\"   DISABLED_style= \"max-width:90%; height:auto;\" > hrs<BR>\n" );
document.write( "-------------------<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+32+=+%28+12+-+c+%29%2At+ ALIGN=MIDDLE  ALT=\"+32+=+%28+12+-+c+%29%2At+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+32+=+%28+12+-+c+%29%2A4+ ALIGN=MIDDLE  ALT=\"+32+=+%28+12+-+c+%29%2A4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+8+=+12+-+c+ ALIGN=MIDDLE  ALT=\"+8+=+12+-+c+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+c+=+4+ ALIGN=MIDDLE  ALT=\"+c+=+4+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The rate of the current is 4 mi/hr<BR>\n" );
document.write( "------------------------------<BR>\n" );
document.write( "check:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+32+=+%28+12+%2B+c+%29%2A%28+6+-+t+%29+ ALIGN=MIDDLE  ALT=\"+32+=+%28+12+%2B+c+%29%2A%28+6+-+t+%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=+32+=+%28+12+%2B+4+%29%2A%28+6+-+4+%29+ ALIGN=MIDDLE  ALT=\"+32+=+%28+12+%2B+4+%29%2A%28+6+-+4+%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=+32+=+16%2A2+ ALIGN=MIDDLE  ALT=\"+32+=+16%2A2+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+32+=+32+ ALIGN=MIDDLE  ALT=\"+32+=+32+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "OK\r<BR>\n" );
document.write( "<BR>\n" );
document.write( "<BR>\n" );
document.write( "\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );