document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=716205>Question 716205</A>: <I><SPAN STYLE=\"word-break: break-all;\"> on a round-trip over the same roads, a car averaged 25 mph going and 30 mph returning. If the entire trip took 5.5 hours, what is the distance each way?<BR>\n" );
document.write( "My question is how can you solve how much time it took for each half of the trip? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #439768 by </B><A HREF=/tutors/aboutme.mpl?userid=Alan3354><B>Alan3354(69443)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Alan3354><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=Alan3354><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=439768\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> on a round-trip over the same roads, a car averaged 25 mph going and 30 mph returning. If the entire trip took 5.5 hours, what is the distance each way?<BR>\n" );
document.write( "My question is how can you solve how much time it took for each half of the trip?<BR>\n" );
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document.write( "The problem doesn't ask for that, it asks for the distance.<BR>\n" );
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document.write( "find the avg speed:<BR>\n" );
document.write( "avg speed = 2*25*30/(25+30) mi/hr<BR>\n" );
document.write( "= 300/11 mi/hr<BR>\n" );
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document.write( "Then d = r*t = (300/11)*5.5 = 150 miles round trip<BR>\n" );
document.write( "--> 75 miles each way.<BR>\n" );
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document.write( "Check:<BR>\n" );
document.write( "75/25 + 75/30 = 3 + 2.5 hours<BR>\n" );
document.write( "= 5.5 hours<BR>\n" );
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document.write( "Avg speed for a round trip is 2*r1*r2/(r1+r2) regardless of the distance<BR>\n" );
document.write( "You can call the distance d and work out the eqn.<BR>\n" );
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document.write( "Another approach:<BR>\n" );
document.write( "The time spent at each speed is inversely proportional to the speed but the ratio is the same as the 2 speeds.<BR>\n" );
document.write( "25x + 30x = 5.5<BR>\n" );
document.write( "55x = 5.5<BR>\n" );
document.write( "x = 0.1<BR>\n" );
document.write( "--> 2.5 hours at the faster speed, 3.0 hours at the slower speed.<BR>\n" );
document.write( " </SPAN>\n" );
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