document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=858788>Question 858788</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Starting at home, Christopher traveled uphill to the hardware store for 24 minutes at just 15 mph. He then traveled back home along the same path downhill at a speed of 30 mph.\r<BR>\n" );
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document.write( "What is his average speed for the entire trip from home to the hardware store and back? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #517453 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=517453\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\">  Starting at home, Christopher traveled uphill to the hardware store for 24 minutes at just 15 mph.<BR>\n" );
document.write( " He then traveled back home along the same path downhill at a speed of 30 mph.<BR>\n" );
document.write( "What is his average speed for the entire trip from home to the hardware store and back?<BR>\n" );
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document.write( "Let d = the one-way distance to the store<BR>\n" );
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document.write( "let a = his average speed for the round trip<BR>\n" );
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document.write( "Write a time equation, time = dist/speed<BR>\n" );
document.write( "time up + time back = total time<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%2F15 ALIGN=MIDDLE  ALT=\"d%2F15\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=d%2F30 ALIGN=MIDDLE  ALT=\"d%2F30\"   DISABLED_style= \"max-width:90%; height:auto;\" > = <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%282d%29%2Fa ALIGN=MIDDLE  ALT=\"%282d%29%2Fa\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "multiply by 30a to clear the denominators, results:<BR>\n" );
document.write( "2ad + ad = 30(2d)<BR>\n" );
document.write( "3ad = 60d<BR>\n" );
document.write( "divide both sides by d<BR>\n" );
document.write( "3a = 60<BR>\n" );
document.write( "a = 60/3<BR>\n" );
document.write( "a = 20 mph is his average speed for the round trip </SPAN>\n" );
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