document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=74280>Question 74280</A>: <I><SPAN STYLE=\"word-break: break-all;\"> I need some help with this problem.\r<BR>\n" );
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document.write( "The speed of a mototboat in still water is 15 mi/hr. If it takes the motorboat the same time to go 15 mi upstream the river as it takes to go 30 mi <BR>\n" );
document.write( "downstream, what is the speed of the current?\r<BR>\n" );
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document.write( "Thank You! </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #53276 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=53276\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The speed of a mototboat in still water is 15 mi/hr. If it takes the motorboat the same time to go 15 mi upstream the river as it takes to go 30 mi <BR>\n" );
document.write( "downstream, what is the speed of the current? <BR>\n" );
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document.write( "Let the rate of the current be \"x\":<BR>\n" );
document.write( "Upstream DATA:<BR>\n" );
document.write( "Distance = 15 mi ; rate = 15-x ; time = d/r = 15(15-x) mph<BR>\n" );
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document.write( "Downstream DATA:<BR>\n" );
document.write( "Distance = 30 mi ; rate = 15+x ; time = d/r = 30/(15+x) mph<BR>\n" );
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document.write( "EQUATION:<BR>\n" );
document.write( "time up = time down<BR>\n" );
document.write( "15/(15-x) = 30/(15+x)<BR>\n" );
document.write( "Divide both sides by 15 to get:<BR>\n" );
document.write( "1/(15-x) = 2/(15+x)<BR>\n" );
document.write( "15+x = 2(15-x)<BR>\n" );
document.write( "15+x = 30-2x<BR>\n" );
document.write( "3x=15<BR>\n" );
document.write( "x=5 mph<BR>\n" );
document.write( "The speed of the current is 5 mph<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
document.write( " </SPAN>\n" );
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