document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=786281>Question 786281</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a boat traveled downstream a distance of 72 mi and then came right back. If the speed of the current at 7 mph and the total trip took 3 hours, find the average speed of the boat relative to the water </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #477862 by </B><A HREF=/tutors/aboutme.mpl?userid=josgarithmetic><B>josgarithmetic(39633)</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=477862\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> r = speed of boat without any river current\r<BR>\n" );
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document.write( "DIRECTION_________rate_____________time__________distance<BR>\n" );
document.write( "down_____________r+7_______________(___)_________72<BR>\n" );
document.write( "up_______________r-7_______________(___)_________72<BR>\n" );
document.write( "Total________________________________3\r<BR>\n" );
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document.write( "Key concept among the numbers <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%2At=d ALIGN=MIDDLE  ALT=\"r%2At=d\"   DISABLED_style= \"max-width:90%; height:auto;\" > where r is rate, t is time, d is distance.  Using this formula allows us <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t=d%2Fr ALIGN=MIDDLE  ALT=\"t=d%2Fr\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "DIRECTION_________rate_______________time__________distance<BR>\n" );
document.write( "down_____________<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%2B7 ALIGN=MIDDLE  ALT=\"r%2B7\"   DISABLED_style= \"max-width:90%; height:auto;\" >_______________<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=72%2F%28r%2B7%29 ALIGN=MIDDLE  ALT=\"72%2F%28r%2B7%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >_________72<BR>\n" );
document.write( "up_______________<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r-7 ALIGN=MIDDLE  ALT=\"r-7\"   DISABLED_style= \"max-width:90%; height:auto;\" >_______________<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=72%2F%28r-7%29 ALIGN=MIDDLE  ALT=\"72%2F%28r-7%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >_________72<BR>\n" );
document.write( "Total_________________________________3\r<BR>\n" );
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document.write( "The time sum should be obvious.  <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=highlight%2872%2F%28r%2B7%29%2B72%2F%28r-7%29=3%29 ALIGN=MIDDLE  ALT=\"highlight%2872%2F%28r%2B7%29%2B72%2F%28r-7%29=3%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply left and right by <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28r%2B7%29%28r-7%29 ALIGN=MIDDLE  ALT=\"%28r%2B7%29%28r-7%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >, and THEN continue to simplify, finally solving for r.  \r<BR>\n" );
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document.write( "Alternatively, <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=72%281%2F%28r%2B7%29%2B1%2F%28r-7%29%29=3 ALIGN=MIDDLE  ALT=\"72%281%2F%28r%2B7%29%2B1%2F%28r-7%29%29=3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=72%28%28r-7%2Br%2B7%29%2F%28r%5E2-49%29%29=3 ALIGN=MIDDLE  ALT=\"72%28%28r-7%2Br%2B7%29%2F%28r%5E2-49%29%29=3\"   DISABLED_style= \"max-width:90%; height:auto;\" >-------(maybe you could keep intermediate steps <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=in+your+head+as+did+I%29 ALIGN=MIDDLE  ALT=\"in+your+head+as+did+I%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=72%282r%29=3%28r%5E2-49%29 ALIGN=MIDDLE  ALT=\"72%282r%29=3%28r%5E2-49%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=24%2A2r=r%5E2-49 ALIGN=MIDDLE  ALT=\"24%2A2r=r%5E2-49\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r%5E2-48r-49=0 ALIGN=MIDDLE  ALT=\"r%5E2-48r-49=0\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "-Use general solution to quadratic formula-<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=%2848%2Bsqrt%2848%5E2-4%28-49%29%29%29%2F2=%2848%2Bsqrt%2848%5E2%2B196%29%29%2F2=%2848%2B50%29%2F2 ALIGN=MIDDLE   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r=98%2F2=49 ALIGN=MIDDLE  ALT=\"r=98%2F2=49\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Boat speed in still water, 49 mph. </SPAN>\n" );
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