document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=432425>Question 432425</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The current in a stream moves at 8mph. A boat travels 19 miles upstream and 19 miles downstream in a total time of 9 hours. What is the speed of the boat in still water?\r<BR>\n" );
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document.write( "All I've been able to come up with is that if it took 9 hours to go 38 miles the boat would be going an average of 4.222mph.<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 #299813 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=299813\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Boat speed		x   		<BR>\n" );
document.write( "current speed 		8		<BR>\n" );
document.write( "				<BR>\n" );
document.write( "against current	x-8 mph		<BR>\n" );
document.write( "with current	x+8	mph	<BR>\n" );
document.write( "				<BR>\n" );
document.write( "Distance= 	19	miles		<BR>\n" );
document.write( "				<BR>\n" );
document.write( "Time against + time with wind = 9 hours<BR>\n" );
document.write( "t=d/r			<BR>\n" );
document.write( "...<BR>\n" );
document.write( "19/(x +	8)+19/(x-8)=9				<BR>\n" );
document.write( "																	<BR>\n" );
document.write( "LCD =(x-8)(x+8)		<BR>\n" );
document.write( "19*(x -	8)+19x+	8)=9				<BR>\n" );
document.write( "19x-152+19x+152	=9(x ^2	-64)<BR>\n" );
document.write( "38x=9x ^2-576											<BR>\n" );
document.write( "9x ^2-38x-576=0								<BR>\n" );
document.write( "Find the roots of the equation by quadratic formula			<BR>\n" );
document.write( "a=	9	b=	-38	c=	-576				<BR>\n" );
document.write( "b^2-4ac=	1444	+	20736					<BR>\n" );
document.write( "b^2-4ac=	22180	:sqrt(22180)=148.93										<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29 ALIGN=MIDDLE  ALT=\"x=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F%282a%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >					<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x1=%28-b%2Bsqrt%28b%5E2-4ac%29%29%2F%282a%29 ALIGN=MIDDLE  ALT=\"x1=%28-b%2Bsqrt%28b%5E2-4ac%29%29%2F%282a%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >						<BR>\n" );
document.write( "x1=(38+148.93)/18												<BR>\n" );
document.write( "x1=10.38 mph																<BR>\n" );
document.write( "x2=(38	-148.93	) /	18													<BR>\n" );
document.write( "x2= -6.16 ( ignore negative)<BR>\n" );
document.write( "speed = 10.38 mph<BR>\n" );
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