document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=157256>Question 157256</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A moving walkway at an airport is 65.0 m long.  A child runing at a constand speek takes 20.0 s to run along the walkway in the direction it is moving, and then 52.0 s to run all the way back.  What are the speed of the walkway and the speed of the child? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #115986 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=115986\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A moving walkway at an airport is 65.0 m long. A child running at a constant<BR>\n" );
document.write( " speed takes 20.0 s to run along the walkway in the direction it is moving,<BR>\n" );
document.write( " and then 52.0 s to run all the way back. What are the speed of the walkway<BR>\n" );
document.write( " and the speed of the child?<BR>\n" );
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document.write( "Let x = speed of the child (meter/sec)<BR>\n" );
document.write( "Let y = speed of the moving sidewalk<BR>\n" );
document.write( "then we can say:<BR>\n" );
document.write( "(x+y) = speed with the walkway<BR>\n" );
document.write( "(x-y) = speed against the walkway<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Write a distance equation for each trip: Dist = time * speed<BR>\n" );
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document.write( "20(x+y) = 65<BR>\n" );
document.write( "52(x-y) = 65<BR>\n" );
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document.write( "20x + 20y = 65<BR>\n" );
document.write( "52x - 52y = 65<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Multiply 1st equation by 52 and 2nd equation by 20, results:<BR>\n" );
document.write( "1040x + 1040y = 3380<BR>\n" );
document.write( "1040x - 1040y = 1300<BR>\n" );
document.write( "----------------------addition eliminates y, find x<BR>\n" );
document.write( "2080x + 0y  = 4680<BR>\n" );
document.write( "x = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=4680%2F2080 ALIGN=MIDDLE  ALT=\"4680%2F2080\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "x = 2.25 m/sec is the child's speed<BR>\n" );
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document.write( "Find y<BR>\n" );
document.write( "20(2.25) + 20y = 65<BR>\n" );
document.write( "45 + 20y = 65<BR>\n" );
document.write( "20y = 65 - 45<BR>\n" );
document.write( "20y = 20<BR>\n" );
document.write( "y = 1 m/sec is the speed of the walkway<BR>\n" );
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document.write( "Check solution in the equation:<BR>\n" );
document.write( "52(2.25-1) = 65<BR>\n" );
document.write( "52(1.25) = 65<BR>\n" );
document.write( "65 = 65; confirms our solutions\r<BR>\n" );
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document.write( " </SPAN>\n" );
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