document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=668197>Question 668197</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Alvin paddled for 4 hourswith a 3km/h current to reach a campsite. The return trip against the same current took 7 hours. What is the speed of the boat in still water? What is the speed of the boat against the current? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #415370 by </B><A HREF=/tutors/aboutme.mpl?userid=swincher4391><B>swincher4391(1107)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=swincher4391><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=swincher4391><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=415370\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let the boat speed in still water be x km/hr.\r<BR>\n" );
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document.write( "We know the current is 3 km/h so:\r<BR>\n" );
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document.write( "4(x+3) =  7(x-3)<BR>\n" );
document.write( "4x + 12 = 7x - 21<BR>\n" );
document.write( "-3x  = -33\r<BR>\n" );
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document.write( "x = 11 km/h<BR>\n" );
document.write( " </SPAN>\n" );
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