document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=193861>Question 193861</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I am not sure how to set this problem up. Can you help?<BR>\n" );
document.write( "You travel 5 miles in a boat. because of a  4 mph current it took you 20 minutes longer to go then return. How fast will you go without current?<BR>\n" );
document.write( "Is the problems set up like-<BR>\n" );
document.write( "10x+100=x^2+20x </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #145544 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=145544\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The equation is <BR>\n" );
document.write( "distance = rate x time but with a modification:<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D ALIGN=MIDDLE  ALT=\"r%5Bs%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >= rate of the boat in still water in mi/hr<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bc%5D ALIGN=MIDDLE  ALT=\"r%5Bc%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >= rate of the current in mi/hr<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%5Bu%5D ALIGN=MIDDLE  ALT=\"t%5Bu%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >= time going upstream in hrs<BR>\n" );
document.write( "Let <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%5Bd%5D ALIGN=MIDDLE  ALT=\"t%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >= time going downstream in hrs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D+-+r%5Bc%5D ALIGN=MIDDLE  ALT=\"r%5Bs%5D+-+r%5Bc%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >= rate of boat against the current in mi/hr<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D+%2B+r%5Bc%5D ALIGN=MIDDLE  ALT=\"r%5Bs%5D+%2B+r%5Bc%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" >= rate of the boat going with the current in mi/hr<BR>\n" );
document.write( "-------------------<BR>\n" );
document.write( "So, going upstream, I can write:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d+=+%28r%5Bs%5D+-+r%5Bc%5D%29%2At%5Bu%5D ALIGN=MIDDLE  ALT=\"d+=+%28r%5Bs%5D+-+r%5Bc%5D%29%2At%5Bu%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "And going downstream, I can write:<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d+=+%28r%5Bs%5D+%2B+r%5Bc%5D%29%2At%5Bd%5D ALIGN=MIDDLE  ALT=\"d+=+%28r%5Bs%5D+%2B+r%5Bc%5D%29%2At%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-------------------<BR>\n" );
document.write( "Given:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d+=+5 ALIGN=MIDDLE  ALT=\"d+=+5\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%5Bu%5D+=+t%5Bd%5D+%2B+20 ALIGN=MIDDLE  ALT=\"t%5Bu%5D+=+t%5Bd%5D+%2B+20\"   DISABLED_style= \"max-width:90%; height:auto;\" > hrs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bc%5D+=+4 ALIGN=MIDDLE  ALT=\"r%5Bc%5D+=+4\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi/hr<BR>\n" );
document.write( "-------------------<BR>\n" );
document.write( "Now I can rewrite (1) and (2)<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+%28r%5Bs%5D+-+4%29%2A%28t%5Bd%5D+%2B+20%29 ALIGN=MIDDLE  ALT=\"5+=+%28r%5Bs%5D+-+4%29%2A%28t%5Bd%5D+%2B+20%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=5+=+%28r%5Bs%5D+%2B+4%29%2At%5Bd%5D ALIGN=MIDDLE  ALT=\"5+=+%28r%5Bs%5D+%2B+4%29%2At%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "This is 2 equation with 2 unknowns, so it's solvable<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+%28r%5Bs%5D+-+4%29%2A%28t%5Bd%5D+%2B+20%29 ALIGN=MIDDLE  ALT=\"5+=+%28r%5Bs%5D+-+4%29%2A%28t%5Bd%5D+%2B+20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+r%5Bs%5D%2At%5Bd%5D+-+4t%5Bd%5D+%2B+20r%5Bs%5D+-+80 ALIGN=MIDDLE  ALT=\"5+=+r%5Bs%5D%2At%5Bd%5D+-+4t%5Bd%5D+%2B+20r%5Bs%5D+-+80\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D%2At%5Bd%5D+%2B+20r%5Bs%5D+=+4t%5Bd%5D+%2B+85 ALIGN=MIDDLE  ALT=\"r%5Bs%5D%2At%5Bd%5D+%2B+20r%5Bs%5D+=+4t%5Bd%5D+%2B+85\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D%2A%28t%5Bd%5D+%2B+20%29+=+4t%5Bd%5D+%2B+85 ALIGN=MIDDLE  ALT=\"r%5Bs%5D%2A%28t%5Bd%5D+%2B+20%29+=+4t%5Bd%5D+%2B+85\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "And, from (2)<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+%28r%5Bs%5D+%2B+4%29%2At%5Bd%5D ALIGN=MIDDLE  ALT=\"5+=+%28r%5Bs%5D+%2B+4%29%2At%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+r%5Bs%5D%2At%5Bd%5D+%2B+4t%5Bd%5D ALIGN=MIDDLE  ALT=\"5+=+r%5Bs%5D%2At%5Bd%5D+%2B+4t%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D%2At%5Bd%5D+=+-+4t%5Bd%5D+%2B+5 ALIGN=MIDDLE  ALT=\"r%5Bs%5D%2At%5Bd%5D+=+-+4t%5Bd%5D+%2B+5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D+=+-4+%2B+5%2Ft%5Bd%5D ALIGN=MIDDLE  ALT=\"r%5Bs%5D+=+-4+%2B+5%2Ft%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "substitute this in (1)<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28-4+%2B+5%2Ft%5Bd%5D%29%2A%28t%5Bd%5D+%2B+20%29+=+4t%5Bd%5D+%2B+85 ALIGN=MIDDLE  ALT=\"%28-4+%2B+5%2Ft%5Bd%5D%29%2A%28t%5Bd%5D+%2B+20%29+=+4t%5Bd%5D+%2B+85\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=-4t%5Bd%5D+%2B+5+-+80+%2B+100%2Ft%5Bd%5D+=+4t%5Bd%5D+%2B+85 ALIGN=MIDDLE  ALT=\"-4t%5Bd%5D+%2B+5+-+80+%2B+100%2Ft%5Bd%5D+=+4t%5Bd%5D+%2B+85\"   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%2A%28t%5Bd%5D%29%5E2+%2B+160t%5Bd%5D+-+100+=+0 ALIGN=MIDDLE  ALT=\"8%2A%28t%5Bd%5D%29%5E2+%2B+160t%5Bd%5D+-+100+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2%2A%28t%5Bd%5D%29%5E2+%2B+40t%5Bd%5D+-+25+=+0 ALIGN=MIDDLE  ALT=\"2%2A%28t%5Bd%5D%29%5E2+%2B+40t%5Bd%5D+-+25+=+0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Using quadratic equation:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%5Bd%5D+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"t%5Bd%5D+=+%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+=+40 ALIGN=MIDDLE  ALT=\"b+=+40\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=c+=+-25 ALIGN=MIDDLE  ALT=\"c+=+-25\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%5Bd%5D+=+%28-40+%2B-+sqrt%28+40%5E2-4%2A2%2A%28-25%29+%29%29%2F%282%2A2%29+ ALIGN=MIDDLE  ALT=\"t%5Bd%5D+=+%28-40+%2B-+sqrt%28+40%5E2-4%2A2%2A%28-25%29+%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=t%5Bd%5D+=+%28-40+%2B-+sqrt%28+1600+%2B+200+%29%29%2F4+ ALIGN=MIDDLE  ALT=\"t%5Bd%5D+=+%28-40+%2B-+sqrt%28+1600+%2B+200+%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=t%5Bd%5D+=+%28-40+%2B-+42.426%29%2F4+ ALIGN=MIDDLE  ALT=\"t%5Bd%5D+=+%28-40+%2B-+42.426%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=t%5Bd%5D+=+2.426%2F4 ALIGN=MIDDLE  ALT=\"t%5Bd%5D+=+2.426%2F4\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t%5Bd%5D+=+.6065 ALIGN=MIDDLE  ALT=\"t%5Bd%5D+=+.6065\"   DISABLED_style= \"max-width:90%; height:auto;\" > hrs<BR>\n" );
document.write( "I want to find <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D ALIGN=MIDDLE  ALT=\"r%5Bs%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D+=+-4+%2B+5%2Ft%5Bd%5D ALIGN=MIDDLE  ALT=\"r%5Bs%5D+=+-4+%2B+5%2Ft%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D+=+-4+%2B+5%2F.6065 ALIGN=MIDDLE  ALT=\"r%5Bs%5D+=+-4+%2B+5%2F.6065\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D+=+-4+%2B+8.244 ALIGN=MIDDLE  ALT=\"r%5Bs%5D+=+-4+%2B+8.244\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5Bs%5D+=+4.244 ALIGN=MIDDLE  ALT=\"r%5Bs%5D+=+4.244\"   DISABLED_style= \"max-width:90%; height:auto;\" > mi/hr answer<BR>\n" );
document.write( "check answer:<BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+%28r%5Bs%5D+-+4%29%2A%28t%5Bd%5D+%2B+20%29 ALIGN=MIDDLE  ALT=\"5+=+%28r%5Bs%5D+-+4%29%2A%28t%5Bd%5D+%2B+20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+%284.244+-+4%29%2A%28.6065+%2B+20%29 ALIGN=MIDDLE  ALT=\"5+=+%284.244+-+4%29%2A%28.6065+%2B+20%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+.244%2A20.6065 ALIGN=MIDDLE  ALT=\"5+=+.244%2A20.6065\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(1) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+5.027 ALIGN=MIDDLE  ALT=\"5+=+5.027\"   DISABLED_style= \"max-width:90%; height:auto;\" > (rounding error?)<BR>\n" );
document.write( "and<BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+%28r%5Bs%5D+%2B+4%29%2At%5Bd%5D ALIGN=MIDDLE  ALT=\"5+=+%28r%5Bs%5D+%2B+4%29%2At%5Bd%5D\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+%284.244+%2B+4%29%2A.6065 ALIGN=MIDDLE  ALT=\"5+=+%284.244+%2B+4%29%2A.6065\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+8.244%2A.6065 ALIGN=MIDDLE  ALT=\"5+=+8.244%2A.6065\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "(2) <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5+=+5 ALIGN=MIDDLE  ALT=\"5+=+5\"   DISABLED_style= \"max-width:90%; height:auto;\" > </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );