document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=123331>Question 123331</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Debbi traveled by boat by 5 miles upstream to fish in her favorite spot. Because of the 4-mhp current, it took her 20 minutes longer to get there than to return. How fast will her boat go 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 #90710 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=90710\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Debbi traveled by boat by 5 miles upstream to fish in her favorite spot. Because of the 4-mhp current, it took her 20 minutes longer to get there than to return. How fast will her boat go in still water?<BR>\n" );
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document.write( "Let s = boat speed in still water<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(s-4) = speed upstream<BR>\n" );
document.write( "and<BR>\n" );
document.write( "(s+4) = speed downstream<BR>\n" );
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document.write( "Change 20 min to hrs: 20/60 = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F3 ALIGN=MIDDLE  ALT=\"1%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" > hr<BR>\n" );
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document.write( "Write a time equation: Time = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Distance%2Fspeed ALIGN=MIDDLE  ALT=\"Distance%2Fspeed\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
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document.write( "Time upstream - time downstream = 20 min (1/3 hr)<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5%2F%28%28s-4%29%29 ALIGN=MIDDLE  ALT=\"5%2F%28%28s-4%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5%2F%28%28s%2B4%29%29 ALIGN=MIDDLE  ALT=\"5%2F%28%28s%2B4%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1%2F3 ALIGN=MIDDLE  ALT=\"1%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply equation by the common denominator 3(s-4)(s+4) and you have:<BR>\n" );
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document.write( "3(s+4)(5) - 3(s-4)(5) = (s+4)(s-4)<BR>\n" );
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document.write( "15(s+4) - 15(s-4) = s^2 - 16<BR>\n" );
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document.write( "15s + 60 - 15s + 60 = s^2 - 16<BR>\n" );
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document.write( "120 = s^2 - 16<BR>\n" );
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document.write( "120 + 16 = s^2<BR>\n" );
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document.write( "s^2 = 136<BR>\n" );
document.write( "s = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=sqrt%28136%29 ALIGN=MIDDLE  ALT=\"sqrt%28136%29\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "s = 11.66 mph boat speed in still water<BR>\n" );
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document.write( "Check solution in original equation using decimals: <BR>\n" );
document.write( "speed upstream = 7.66<BR>\n" );
document.write( "speed downstream = 15.66<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5%2F%287.66%29 ALIGN=MIDDLE  ALT=\"5%2F%287.66%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5%2F%2815.66%29 ALIGN=MIDDLE  ALT=\"5%2F%2815.66%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > =<BR>\n" );
document.write( " .653 - .319 = .333; confirms our solution of s = 11.66<BR>\n" );
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