document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=981685>Question 981685</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Please help me with this problem.<BR>\n" );
document.write( "Write an equation that can be used to solve the problem. Solve the equation and answer the question. A sigh- seeing boat travels at an average speed of 20 miles per hour in the calm water of a large lake. The same boat is used for sigh- seeing in a nearby river. In the river the boat travels 2.9 miles downstream (with the current) in the same amount of time it takes to travel 2.5 miles upstream (against the current) <BR>\n" );
document.write( "Find the current of the river. <BR>\n" );
document.write( "This is a very large problem and I would be extremely grateful if you could help me. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #602647 by </B><A HREF=/tutors/aboutme.mpl?userid=macston><B>macston(5194)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=macston><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=macston><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=602647\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> .<BR>\n" );
document.write( "c=speed of current<BR>\n" );
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document.write( "time upstream=distance/rate=2.5mi/(20mph-c)<BR>\n" );
document.write( ".<BR>\n" );
document.write( "time downstream=distance/rate=2.9mi/(20mph+c)<BR>\n" );
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document.write( "Since it takes the same amount of time:<BR>\n" );
document.write( "2.5mi/(20mph-c)=2.9mi/(20mph+c) Cross multiply.<BR>\n" );
document.write( "(2.5mi)(20mph+c)=(2.9mi)(20mph-c)<BR>\n" );
document.write( "50 mi^2/hr+2.5c mi=58mi^2/hr-2.9c mi Subtract 50mi^2/hr from each side.<BR>\n" );
document.write( "2.5c mi=8mi^2/hr-2.9c mi Add 2.9c mi to each side.<BR>\n" );
document.write( "5.4c mi=8mi^2/hr Divide each side by 5.4 mi.<BR>\n" );
document.write( "c=1.48 mi/hr ANSWER: The rate of the current was 1.48 mph.<BR>\n" );
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document.write( "CHECK:<BR>\n" );
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document.write( "2.5mi/(20mph-c)=2.9mi/(20mph+c)<BR>\n" );
document.write( "2.5mi/(20mph-1.48mph)=2.9mi/(20mph+1.48mph)<BR>\n" );
document.write( "2.5mi/18.52mph=2.9mi/21.48mph<BR>\n" );
document.write( "0.135 hr=0.135 hr<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );