document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1157574>Question 1157574</A>: <I><SPAN STYLE=\"word-break: break-all;\"> To get to his parents' house, John must travel at a speed of 60 mph on land and then use a motorboat that travels at a speed of 20 mph in still water. John goes by land to a dock and then travels on a river against a current of 4 mph. He reaches his parent's home in 4.5 hours. The return trip takes him 3.5 hours. How far do his parents live from his house?\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 #780455 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=780455\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> \r<BR>\n" );
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document.write( "speed of 60 mph on land  let distance be x  <BR>\n" );
document.write( "and then use a motorboat that travels at a speed of 20 mph in still water.<BR>\n" );
document.write( "against current speed = 20-4=16 mph. River distance be y\r<BR>\n" );
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document.write( "Time forward journey <BR>\n" );
document.write( "x/60 +y/16 = 4.5\r<BR>\n" );
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document.write( "Time return motorboat<BR>\n" );
document.write( "speed = 20+4 =24 (with current)<BR>\n" );
document.write( "x/60+y/24 =3.5\r<BR>\n" );
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document.write( "x/60 +y/16 = 4.5<BR>\n" );
document.write( "60y+16x= 60*16*4.5\r<BR>\n" );
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document.write( "x/60+y/24 =3.5\r<BR>\n" );
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document.write( "60y+24x = 60*24*3.5\r<BR>\n" );
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document.write( "16.00	x	+	60.00	y	=	4320.00			<BR>\n" );
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document.write( "24.00	x	+	60.00	y	=	5040.00	.............2		<BR>\n" );
document.write( "Eliminate 	y								<BR>\n" );
document.write( "multiply (1)by		-1.00							<BR>\n" );
document.write( "Multiply (2) by		1.00							<BR>\n" );
document.write( "-16.00	x		-60.00	y	=	-4320.00			<BR>\n" );
document.write( "24.00	x		60.00	y	=	5040.00			<BR>\n" );
document.write( "Add the two equations									<BR>\n" );
document.write( "8.00	x				=	720.00			<BR>\n" );
document.write( "/	8.00								<BR>\n" );
document.write( "x	=	90.00							<BR>\n" );
document.write( "plug value of			x	in (1)					<BR>\n" );
document.write( "16.00	x	+	60.00	y	=	4320.00			<BR>\n" );
document.write( "1440.00		+	60.00	y	=	4320.00			<BR>\n" );
document.write( "			60.00	y	=	2880.00			<BR>\n" );
document.write( "				y	=	48.00			<BR>\n" );
document.write( "Ans	x	=	90.00						<BR>\n" );
document.write( "	y	=	48.00						\r<BR>\n" );
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