document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=918878>Question 918878</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Correct Question:  Two campers left the camp at 8:00 AM to paddle their canoe 10 km upstream to a fishing cove.  They fished for 3.5 hours then paddle back to the campsite and arrived at 6:00 PM. If the rate of the current was 3 km/h, how fast could the campers paddle 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 #557459 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=557459\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Correct Question: Two campers left the camp at 8:00 AM to paddle their canoe 10 km upstream to a fishing cove. They fished for 3.5 hours then paddle back to the campsite and arrived at 6:00 PM. If the rate of the current was 3 km/h, how fast could the campers paddle in still water?<BR>\n" );
document.write( "***<BR>\n" );
document.write( "let x=speed campers can paddle in still water<BR>\n" );
document.write( "x+3=speed campers can paddle downstream<BR>\n" );
document.write( "x-3=speed campers can paddle upstream<BR>\n" );
document.write( "distance/speed=travel time<BR>\n" );
document.write( "..<BR>\n" );
document.write( "10/(x-3)+3.5+10/(x+3)=10(8 AM to 6 PM)<BR>\n" );
document.write( "10/(x-3)+10/(x+3)=6.5<BR>\n" );
document.write( "lcd:(x+3)(x-3)<BR>\n" );
document.write( "10(x+3)+10(x-3)=6.5(x^2-9)<BR>\n" );
document.write( "10x+30+10x-30=6.5x^2-58.5<BR>\n" );
document.write( "20x=6.5x^2-58.5<BR>\n" );
document.write( "6.5x^2-20x-58.5<BR>\n" );
document.write( "solve for x by quadratic formula:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ ALIGN=MIDDLE  ALT=\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "a=6.5, b=-20, c=-58.5<BR>\n" );
document.write( "ans:<BR>\n" );
document.write( "x=4.9<BR>\n" );
document.write( "speed campers can paddle in still water=4.9 km/hr<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );