document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=204259>Question 204259</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A boat can travel 14 miles upstream in the same amount of time it takes to travel 21 miles downstream. If the current is 2 miles per hour, what is the speed of the boat in still water? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #154225 by </B><A HREF=/tutors/aboutme.mpl?userid=Earlsdon><B>Earlsdon(6294)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Earlsdon><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=154225\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Use the distance formula:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d+=+r%2At ALIGN=MIDDLE  ALT=\"d+=+r%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" > where: d = distance trveled, r = rate(speed), and t = time of travel.<BR>\n" );
document.write( "For the trip upstream (against the current of 2mph), d = 14mi. and r = speed of the boat, so you can write:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=14+=+%28r-2%29%2At ALIGN=MIDDLE  ALT=\"14+=+%28r-2%29%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" > The speed of the current is subtracted from the speed of the boat going upstream.<BR>\n" );
document.write( "For the trip downstream (with the current of 2mph), d = 21mi, and r = the speed of the boat, so you can write:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=21+=+%28r%2B2%29%2At ALIGN=MIDDLE  ALT=\"21+=+%28r%2B2%29%2At\"   DISABLED_style= \"max-width:90%; height:auto;\" > The time, t, is the same in both cases, so we solve both equations for t and set them equal to each other.<BR>\n" );
document.write( "Upstream trip:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+14%2F%28r-2%29 ALIGN=MIDDLE  ALT=\"t+=+14%2F%28r-2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Downstream trip:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=t+=+21%2F%28r%2B2%29 ALIGN=MIDDLE  ALT=\"t+=+21%2F%28r%2B2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Set these equal to each other.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=14%2F%28r-2%29+=+21%2F%28r%2B2%29 ALIGN=MIDDLE  ALT=\"14%2F%28r-2%29+=+21%2F%28r%2B2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Solve for r, the speed of the boat in still water. Cross multiply.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=14%28r%2B2%29+=+21%28r-2%29 ALIGN=MIDDLE  ALT=\"14%28r%2B2%29+=+21%28r-2%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > Simplify.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=14r%2B28+=+21r-42 ALIGN=MIDDLE  ALT=\"14r%2B28+=+21r-42\"   DISABLED_style= \"max-width:90%; height:auto;\" > Subtract 14r from both sides.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=28+=+7r-42 ALIGN=MIDDLE  ALT=\"28+=+7r-42\"   DISABLED_style= \"max-width:90%; height:auto;\" > Add 42 to both sides.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=70+=+7r ALIGN=MIDDLE  ALT=\"70+=+7r\"   DISABLED_style= \"max-width:90%; height:auto;\" > Finally, divide both sides by 7.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=r+=+10 ALIGN=MIDDLE  ALT=\"r+=+10\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "The speed of the boat in still water is 10mph.\r<BR>\n" );
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document.write( " </SPAN>\n" );
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