document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=834068>Question 834068</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Jerry rowed upstream against a 2 mile-per-hour current a distance of 12 miles to his camp. He returned rowing downstream later in the day. If the total time first trip was 8 hours, find the time it took rowing for each part of the trip </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #502886 by </B><A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><B>ankor@dixie-net.com(22740)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=ankor@dixie-net.com><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=ankor@dixie-net.com><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=502886\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Jerry rowed upstream against a 2 mile-per-hour current a distance of 12 miles to his camp.<BR>\n" );
document.write( " He returned rowing downstream later in the day.<BR>\n" );
document.write( " If the total time for the trip was 8 hours, find the time it took rowing for each part of the trip<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Let s = rowing speed in still water<BR>\n" );
document.write( "If we know his rowing speed in still water, we can find the time each way<BR>\n" );
document.write( ":<BR>\n" );
document.write( "(s-2) = his effective speed upstream<BR>\n" );
document.write( "and<BR>\n" );
document.write( "(s+2) = his effective speed downstream<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Write a time equation, time = dist/speed<BR>\n" );
document.write( "time up + time down = 8 hrs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12%2F%28%28s-2%29%29 ALIGN=MIDDLE  ALT=\"12%2F%28%28s-2%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=12%2F%28%28s%2B2%29%29 ALIGN=MIDDLE  ALT=\"12%2F%28%28s%2B2%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 8<BR>\n" );
document.write( "multiply eq by (s-2)(s+2); cancel the denominators and we have<BR>\n" );
document.write( "12(s+2) + 12(s-2) = 8(s-2)(s+2)<BR>\n" );
document.write( "12s + 24 + 12s - 24 = 8(s^2-4)<BR>\n" );
document.write( "24s = 8s^2 - 32<BR>\n" );
document.write( "0 = 8s^2 - 24s - 32<BR>\n" );
document.write( "simplify, divide by 8<BR>\n" );
document.write( "s^2 - 3s - 4 = 0<BR>\n" );
document.write( "Factors to <BR>\n" );
document.write( "(s-4)(s+1) = 0<BR>\n" );
document.write( "the positive solution<BR>\n" );
document.write( "s = 4 mph in still water<BR>\n" );
document.write( "then<BR>\n" );
document.write( "2 mph upstream and 6 mph downstream<BR>\n" );
document.write( "Find the times<BR>\n" );
document.write( "12/2 = 6 hrs upstream<BR>\n" );
document.write( "12/6 - 2 hrs downstream<BR>\n" );
document.write( "-----------------------<BR>\n" );
document.write( "total time 8 hrs<BR>\n" );
document.write( " </SPAN>\n" );
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