document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=444914>Question 444914</A>: <I><SPAN STYLE=\"word-break: break-all;\"> in still water a boat travels 15 mph. It takes same amount of time to travel 20 miles downstream, with the current, as 10 miles upstream against the current.what is the rate of the waters current? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #306609 by </B><A HREF=/tutors/aboutme.mpl?userid=htmentor><B>htmentor(1343)</B></A><img src=\"/images/stars/stars-12.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=htmentor><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=htmentor><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=306609\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let c = the speed of the current<BR>\n" );
document.write( "The 20 mile downstream travel time will be 20/(15+c)<BR>\n" );
document.write( "The 10 mile upstream travel time will be 10/(15-c)<BR>\n" );
document.write( "Since the times are equal we have<BR>\n" );
document.write( "20/(15+c) = 10/(15-c)<BR>\n" );
document.write( "Solve for c:<BR>\n" );
document.write( "10(15+c) = 20(15-c)<BR>\n" );
document.write( "15+c = 30-2c<BR>\n" );
document.write( "3c = 15<BR>\n" );
document.write( "c = 5<BR>\n" );
document.write( "So the rate of the current is 5 mph<BR>\n" );
document.write( "Check:<BR>\n" );
document.write( "t = 20/(15+5) = 1 hr<BR>\n" );
document.write( "t = 10/(15-5) = 1 hr </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );