document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=717717>Question 717717</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the speed of a current is 4 mph. if a boat travels 75 miles down stream in the same time it takes to travel 39 miles up stream, 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 #440531 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><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=440531\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the speed of a current is 4 mph. if a boat travels 75 miles down stream in the same time it takes to travel 39 miles up stream, what is the speed of the boat in still water<BR>\n" );
document.write( "***<BR>\n" );
document.write( "let x=speed of the boat in still water<BR>\n" );
document.write( "x+4=speed of the boat downstream<BR>\n" );
document.write( "x-4=speed of the boat upstream<BR>\n" );
document.write( "travel time=distance/speed<BR>\n" );
document.write( "..<BR>\n" );
document.write( "75/(x+4)=39/(x-4)<BR>\n" );
document.write( "75x-300=39x+156<BR>\n" );
document.write( "36x=456<BR>\n" );
document.write( "x=12.67 (rounded)<BR>\n" );
document.write( "speed of the boat in still water=12.67 mph </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );