document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=514279>Question 514279</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a river is flowing at a rate of 5kph a boat travels 12km upstream and 36 km downstream in a total of 9hrs.what is the speed of the boat in stilll water? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #343379 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=343379\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Boat speed	x	mph														<BR>\n" );
document.write( "current speed 	5	mph														<BR>\n" );
document.write( "																<BR>\n" );
document.write( "Distance with current	36	miles														<BR>\n" );
document.write( "Distance against current	12	miles														<BR>\n" );
document.write( "																<BR>\n" );
document.write( "spee with current	x	+	5	mph												<BR>\n" );
document.write( "spee against  current=	x		-5	mph												<BR>\n" );
document.write( "Total   time =		9	hours													<BR>\n" );
document.write( "Time with current=		36	/(	x	+	5	)									<BR>\n" );
document.write( "time against current 		12	/	(	x	-5	)									<BR>\n" );
document.write( "																<BR>\n" );
document.write( "Time with  current + time against  =			9	hours												<BR>\n" );
document.write( "																<BR>\n" );
document.write( "36/(x +	5 )	+	12	/(x	-5	)	=	9				<BR>\n" );
document.write( "LCD =	(	x	+	5	)*	(x	-5	)								<BR>\n" );
document.write( "multiply the equation by the LCD																<BR>\n" );
document.write( "we get																<BR>\n" );
document.write( "3*(x	-5)+	12	(x	+5)=	9	(x^2		-25	)<BR>\n" );
document.write( "36)x	-180	+	 12	x	+	60	)	=	9	X^2		-225			<BR>\n" );
document.write( "48	x	-120	=	9	X^2		-225									<BR>\n" );
document.write( "9	X^2	-48	x	120	+	-225	=	0								<BR>\n" );
document.write( "9	X^2+	-48	x+	-105	=	0										<BR>\n" );
document.write( "/	9															<BR>\n" );
document.write( "1	X^2	-5.33	x	-11.67	=	0										<BR>\n" );
document.write( "																<BR>\n" );
document.write( "	Find the roots of the equation by quadratic formula															<BR>\n" );
document.write( "																<BR>\n" );
document.write( "	a=	1	,b=	-5.33	,c=	-11.67										<BR>\n" );
document.write( "																<BR>\n" );
document.write( "	b^2-4ac=	28.41	+	46.68												<BR>\n" );
document.write( "	b^2-4ac=	75.09														<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;\" >							49.98								<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( "	<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x1=%28-12%2B21%29%2F%2812%29 ALIGN=MIDDLE  ALT=\"x1=%28-12%2B21%29%2F%2812%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >															<BR>\n" );
document.write( "	x1=(	5.33	+	8.67	)/	2										<BR>\n" );
document.write( "	x1=	7										7      				<BR>\n" );
document.write( "	x2=(	5.33	-8.67	) /	2											<BR>\n" );
document.write( "	x2= 	-1.67														<BR>\n" );
document.write( "	Ignore negative value															<BR>\n" );
document.write( "	Boat speed	=	7	mph												<BR>\n" );
document.write( "																<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );