document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=975138>Question 975138</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Here is my question:\r<BR>\n" );
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document.write( "A boat travels 12km upstream and back in 3 hours. If the speed of the current is 3 km/h throughout, make an equation and find the speed of the boat in still water.\r<BR>\n" );
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document.write( "Thank you very much! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #596946 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39799)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=596946\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> r, boat if no current<BR>\n" );
document.write( "c, current<BR>\n" );
document.write( "d, distance each way<BR>\n" );
document.write( "t, total time up and back\r<BR>\n" );
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document.write( "RT=D basic uniform rates travel relationship\r<BR>\n" );
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document.write( "__________________speed__________time__________distance<BR>\n" );
document.write( "UP________________r-c____________d/(r-c)___________d<BR>\n" );
document.write( "BK________________r+c____________d/(r+c)___________d<BR>\n" );
document.write( "Total____________________________t____________2d\r<BR>\n" );
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document.write( "UNKNOWN VARIABLES:  r<BR>\n" );
document.write( "KNOWN:  c, t, d.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight_green%28d%2F%28r-c%29%2Bd%2F%28r%2Bc%29=t%29 ALIGN=MIDDLE  ALT=\"highlight_green%28d%2F%28r-c%29%2Bd%2F%28r%2Bc%29=t%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >, and you want to solve for r.\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%28r%2Bc%29%2Bd%28r-c%29=t%28r-c%29%28r%2Bc%29 ALIGN=MIDDLE  ALT=\"d%28r%2Bc%29%2Bd%28r-c%29=t%28r-c%29%28r%2Bc%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=dr%2Bcd%2Bdr-dc=t%28r%5E2-c%5E2%29 ALIGN=MIDDLE  ALT=\"dr%2Bcd%2Bdr-dc=t%28r%5E2-c%5E2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=2dr=tr%5E2-tc%5E2 ALIGN=MIDDLE  ALT=\"2dr=tr%5E2-tc%5E2\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=tr%5E2-2dr-tc%5E2=0 ALIGN=MIDDLE  ALT=\"tr%5E2-2dr-tc%5E2=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "You might expect that as an academic exercise, that the trinomial may be factorable, but staying completely in symbols,\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=%282d%2B-+sqrt%284d%5E2%2B4t%2Atc%5E2%29%29%2F%282t%29 ALIGN=MIDDLE  ALT=\"r=%282d%2B-+sqrt%284d%5E2%2B4t%2Atc%5E2%29%29%2F%282t%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=%282d%2B-+2sqrt%28d%5E2%2Bt%5E2c%5E2%29%29%2F%282t%29 ALIGN=MIDDLE  ALT=\"r=%282d%2B-+2sqrt%28d%5E2%2Bt%5E2c%5E2%29%29%2F%282t%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%28r=%28d%2B-+sqrt%28d%5E2%2B%28tc%29%5E2%29%29%2Ft%29 ALIGN=MIDDLE  ALT=\"highlight%28r=%28d%2B-+sqrt%28d%5E2%2B%28tc%29%5E2%29%29%2Ft%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "You would want the PLUS form.  Substitute the given values for d, t, c, and evaluate r. </SPAN>\n" );
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