document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=405959>Question 405959</A>: <I><SPAN STYLE=\"word-break: break-all;\">  A boat traveled downstream a distance of 95 miles and then came right back. If the speed of the current was 8 mph and the total trip took 6 hours and 20 min, find the average speed of the boat relative to the water </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #286726 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=286726\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A boat traveled downstream a distance of 95 miles and then came right back.<BR>\n" );
document.write( " If the speed of the current was 8 mph and the total trip took 6 hours and <BR>\n" );
document.write( "20 min, find the average speed of the boat relative to the 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+8) = speed (relative to land) downstream<BR>\n" );
document.write( "and<BR>\n" );
document.write( "(s-8) = speed upstream<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Change 6 hr 20 min to 6<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;\" > hrs<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Write a time equation: time = dist/speed<BR>\n" );
document.write( ":<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=95%2F%28s%2B8%29 ALIGN=MIDDLE  ALT=\"95%2F%28s%2B8%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=95%2F%28s-8%29 ALIGN=MIDDLE  ALT=\"95%2F%28s-8%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 6<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( "change to an improper fraction<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=95%2F%28s%2B8%29 ALIGN=MIDDLE  ALT=\"95%2F%28s%2B8%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=95%2F%28s-8%29 ALIGN=MIDDLE  ALT=\"95%2F%28s-8%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=19%2F3 ALIGN=MIDDLE  ALT=\"19%2F3\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( ":<BR>\n" );
document.write( "Multiply by 3(s+8)(s-8), results:<BR>\n" );
document.write( "95*3(s-8) + 95*3(s+8) = 19(s+8)(s-8)<BR>\n" );
document.write( ":<BR>\n" );
document.write( "95(3s-24) + 95(3s+24) = 19(s^2-64)<BR>\n" );
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document.write( "285s - 2280 + 285s + 2280 = 19s^2 - 1216<BR>\n" );
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document.write( "570s = 19s^2 - 1216<BR>\n" );
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document.write( "A quadratic equation<BR>\n" );
document.write( "19s^2 - 570s - 1216 = 0<BR>\n" );
document.write( "divide by 19<BR>\n" );
document.write( "s^2 - 30s - 64 = 0<BR>\n" );
document.write( "Factors to<BR>\n" );
document.write( "(s+2)(s-32) = 0<BR>\n" );
document.write( "The positive solution<BR>\n" );
document.write( "s = 32 mph is the boat speed relative to the water<BR>\n" );
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document.write( "Confirm this by finding the time for each half of the trip<BR>\n" );
document.write( "95/40 = 2.375 hrs<BR>\n" );
document.write( "95/24 = 3.958 hrs<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "total = 6.333 hrs which is 6 hr 20 min<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );