document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=471491>Question 471491</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A motorboat maintained a constant speed of 11 miles per hour relative to water in Goin 30 miles upstream and then returning. The total time for the trip was 5.5 hours. Use this information to find the speed of the current\r<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #323421 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=323421\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A motorboat maintained a constant speed of 11 miles per hour relative to water in Going 30 miles upstream and then returning.<BR>\n" );
document.write( " The total time for the trip was 5.5 hours.<BR>\n" );
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document.write( "Let c = speed of the current<BR>\n" );
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document.write( "(11+c) = speed downstream relative to land<BR>\n" );
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document.write( "(11-c) = speed upstream relative to the land<BR>\n" );
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document.write( "Write a time equation: time = dist/speed<BR>\n" );
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document.write( "time upstream + time downstream = 5.5 hrs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=30%2F%28%2811-c%29%29 ALIGN=MIDDLE  ALT=\"30%2F%28%2811-c%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=30%2F%28%2811%2Bc%29%29 ALIGN=MIDDLE  ALT=\"30%2F%28%2811%2Bc%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 5.5 <BR>\n" );
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document.write( "Multiply by (11-c)(11+c), results:<BR>\n" );
document.write( "30(11+c) + 30(11-c) = 5.5(11+c)(11-c)<BR>\n" );
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document.write( "330 + 30c + 330 - 30c = 5.5(121 - 11c + 11c - c^2)<BR>\n" );
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document.write( "660 = 5.5(121 - c^2)<BR>\n" );
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document.write( "660 = 665.5 - 5.5c^2<BR>\n" );
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document.write( "5.5c^2 = 665.5 - 660<BR>\n" );
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document.write( "5.5c^2 = 5.5<BR>\n" );
document.write( "Divide both sides by 5.5<BR>\n" );
document.write( "c^2 = 1<BR>\n" );
document.write( "c = 1 mph is the current<BR>\n" );
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document.write( "See if this is true; find the times both ways<BR>\n" );
document.write( "downstream: 30/12 = 2.5 hrs<BR>\n" );
document.write( "up-stream:  30/10 = 3.0 hrs<BR>\n" );
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document.write( "total time: 5.5 hrs </SPAN>\n" );
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