document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=264590>Question 264590</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A boat can go 45 mph in still water. It takes as long to go 630 miles upstream as it does to go downstream 720 miles. How fast is 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 #194793 by </B><A HREF=/tutors/aboutme.mpl?userid=Ruli><B>Ruli(21)</B></A><img src=\"/images/stars/stars-07.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Ruli><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=194793\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> 630 miles upstrem = 630/(45-x)<BR>\n" );
document.write( "720 miles downstream 720/(45+x)<BR>\n" );
document.write( "630/(45-x) = 720/(45+x)<BR>\n" );
document.write( "Multiply each side by (45-x)(45+x)<BR>\n" );
document.write( "630(45+x) = 720(45-x)<BR>\n" );
document.write( "28,350 + 630x = 32,400 - 720x<BR>\n" );
document.write( "28,350 + 630x + 720x = 32,400 - 720x + 720x<BR>\n" );
document.write( "28,350 + 1350x - 28,350 = 32,400 - 28,350<BR>\n" );
document.write( "1350x = 4050<BR>\n" );
document.write( "Divide each side by 1350<BR>\n" );
document.write( "x = 3<BR>\n" );
document.write( "The speed of the currecnt is 3 mph<BR>\n" );
document.write( "Check:<BR>\n" );
document.write( "630/(45-3) = 720/(45+3)<BR>\n" );
document.write( "630/(42) = 720/(48)<BR>\n" );
document.write( "15 = 15 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );