document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1030814>Question 1030814</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Mary and Richard leave Edmonton to go to Jasper, a distance of 400 km.  Mary drives at an average speed of 15 km/h faster than Richard.  If Mary arrives in Jasper 40 minutes before Richard, find Richard's average speed, to the nearest km/h. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #645638 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=645638\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Mary and Richard leave Edmonton to go to Jasper, a distance of 400 km.  Mary drives at an average speed of 15 km/h faster than Richard.  If Mary arrives in Jasper 40 minutes before Richard, find Richard's average speed, to the nearest km/h.\r<BR>\n" );
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document.write( "Let Richard,s speed be x\r<BR>\n" );
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document.write( "Mary's speed = x+15\r<BR>\n" );
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document.write( "Time taken by Richard - time taken by Mary = 40 minutes = 2/3 hours\r<BR>\n" );
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document.write( "400/x - 400/(x+15) = 2/3\r<BR>\n" );
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document.write( "400(x+15)-400x = (2/3) *x(x+15)\r<BR>\n" );
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document.write( "6000 = (2/3) *x(x+15)\r<BR>\n" );
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document.write( "18000 = 2x^2 +30x <BR>\n" );
document.write( "/2 and rearrange\r<BR>\n" );
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document.write( "x^2 +15x -9000 =0\r<BR>\n" );
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document.write( "a=	1	,	b=	15		c=	-9000	<BR>\n" );
document.write( "								<BR>\n" );
document.write( "b^2-4ac=	225	+	36000					<BR>\n" );
document.write( "b^2-4ac=	36225							<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%09sqrt%28%0936225%09%29=%09190.33%09 ALIGN=MIDDLE  ALT=\"%09sqrt%28%0936225%09%29=%09190.33%09\"   DISABLED_style= \"max-width:90%; height:auto;\" >			<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=(	-15	+	190.33	)/	2			<BR>\n" );
document.write( "x1=	87.66							<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=x2=%28-b-sqrt%28b%5E2-4ac%29%29%2F%282a%29 ALIGN=MIDDLE  ALT=\"x2=%28-b-sqrt%28b%5E2-4ac%29%29%2F%282a%29\"   DISABLED_style= \"max-width:90%; height:auto;\" >								<BR>\n" );
document.write( "x2=(	-15	-190.33	) /	2				<BR>\n" );
document.write( "x2=	-102.66							<BR>\n" );
document.write( "Ignore negative value								<BR>\n" );
document.write( "	Richard's speed	=87.66	mph					\r<BR>\n" );
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document.write( " </SPAN>\n" );
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