document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=931844>Question 931844</A>: <I><SPAN STYLE=\"word-break: break-all;\"> jon recently drove to visit his parents who live 456 miles away on his way there his average speed was 14 mph faster than his drive there. jon spent a total of 19 hours driving </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #565898 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=565898\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> jon recently drove to visit his parents who live 456 miles away<BR>\n" );
document.write( " on his way there his average speed was 14 mph faster than his drive back.<BR>\n" );
document.write( " jon spent a total of 19 hours driving<BR>\n" );
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document.write( "Assume you are looking for his average speed<BR>\n" );
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document.write( "let s = his speed to his parents<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(s-14) = his return speed<BR>\n" );
document.write( ";<BR>\n" );
document.write( "write a time equation; time = dist/speed<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=456%2Fs ALIGN=MIDDLE  ALT=\"456%2Fs\"   DISABLED_style= \"max-width:90%; height:auto;\" > + <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=456%2F%28%28s-14%29%29 ALIGN=MIDDLE  ALT=\"456%2F%28%28s-14%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = 19<BR>\n" );
document.write( "multiply eq by s(s-14), cancel the denominators and you have<BR>\n" );
document.write( "456(s-14) + 456s = 19s(s-14)<BR>\n" );
document.write( "456s - 6384 + 456s = 19s^2 - 266s<BR>\n" );
document.write( "912s - 6384 = 19s^2 - 266x<BR>\n" );
document.write( "a quadratic equation<BR>\n" );
document.write( "19s^2 - 266s - 912s + 6384 = 0<BR>\n" );
document.write( "19s^2 - 1178s + 6384 = 0<BR>\n" );
document.write( "using the quadratic formula I got<BR>\n" );
document.write( "s = 6<BR>\n" );
document.write( "s = 56, obviously the only reasonable answer<BR>\n" );
document.write( ":<BR>\n" );
document.write( "He went 56 mph there and returned at 42 mph (14 mph less)<BR>\n" );
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document.write( "See if that checks out; find the actual time each way<BR>\n" );
document.write( "456/56 = 8.143 hrs<BR>\n" );
document.write( "456/42 = 10.857 hrs<BR>\n" );
document.write( "------------------<BR>\n" );
document.write( "total time 19.00 hrs? </SPAN>\n" );
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