document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=590190>Question 590190</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A boat takes 3 hours to go 42 miles downstream with the current. It takes 4.2 hours to go 42 miles upstream against the current. What is the speed of the current? What is the speed of the boat? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #375079 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=375079\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A boat takes 3 hours to go 42 miles downstream with the current. It takes 4.2 hours to go 42 miles upstream against the current. What is the speed of the current? What is the speed of the boat?<BR>\n" );
document.write( "**<BR>\n" );
document.write( "let x=speed of the boat<BR>\n" );
document.write( "let c=speed of the current<BR>\n" );
document.write( "net speed with current=x+c<BR>\n" );
document.write( "net speed against current=x-c<BR>\n" );
document.write( "speed=distance/travel time<BR>\n" );
document.write( "..<BR>\n" );
document.write( "(x+c)=42/3=14<BR>\n" );
document.write( "(x-c)=42/4.2=10<BR>\n" );
document.write( "..<BR>\n" );
document.write( "x+c=14<BR>\n" );
document.write( "x-c=10<BR>\n" );
document.write( "add, eliminating c<BR>\n" );
document.write( "2x=24<BR>\n" );
document.write( "x=12<BR>\n" );
document.write( "c=14-x=14-12=2<BR>\n" );
document.write( "ans: <BR>\n" );
document.write( "speed of the boat=12 mph<BR>\n" );
document.write( "speed of the current=2 mph<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );