document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=368912>Question 368912</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a boat travels 2 km upstream in 2 km back. The time for the round trip is 7 hours.The speed of the stream is 2 km/hr. What is the speed of the boat in still water<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #262869 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=262869\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> let speed of boat in still water be x kmph<BR>\n" );
document.write( "speed of current = 2 kmph<BR>\n" );
document.write( "..<BR>\n" );
document.write( "upstream speed = x-2 <BR>\n" );
document.write( "downstream speed = x+2<BR>\n" );
document.write( "..<BR>\n" );
document.write( "t= d/r<BR>\n" );
document.write( "time upstream + time downstream = 7 hours<BR>\n" );
document.write( "distance = 2km<BR>\n" );
document.write( "2/(x-2)+2/(x+2)=7<BR>\n" );
document.write( "2(x+2)+2(x-2)/(x+2)(x-2)=7<BR>\n" );
document.write( "2x+4+2x-4 = 7(x+2)(x-2)<BR>\n" );
document.write( "4x=7(x^2-4)<BR>\n" );
document.write( "4x=7x^2-28<BR>\n" );
document.write( "7x^2-4x-28 =0<BR>\n" );
document.write( "solve using quadratic equation<BR>\n" );
document.write( "discriminant = 800<BR>\n" );
document.write( "x1= (+4+sqrt(800))/14<BR>\n" );
document.write( "x1= 2.3 km/h speed of boat in still water<BR>\n" );
document.write( "x2 is negative so ignore<BR>\n" );
document.write( "...<BR>\n" );
document.write( "m.ananth@hotmail.ca </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );