document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=606716>Question 606716</A>: <I><SPAN STYLE=\"word-break: break-all;\"> a bus driver wants to average at least 40  mph on a 70-mi trip. if the first 35 mi take the driver 1 hr, what should be the lowest average speed for the second 35 mi?<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #382198 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=382198\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> a bus driver wants to average at least 40  mph on a 70-mi trip. if the first 35 mi take the driver 1 hr, what should be the lowest average speed for the second 35 mi?<BR>\n" );
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document.write( "For a round-trip, or with parts of equal length, the avg speed is<BR>\n" );
document.write( "Avg = 2*r1*r2/(r1 + r2)<BR>\n" );
document.write( "40 = 2*35*r2/(35 + r2)<BR>\n" );
document.write( "1400 + 40r2 = 70r2<BR>\n" );
document.write( "r2 = 1400/30 mi/hr<BR>\n" );
document.write( "140/3 mi/hr<BR>\n" );
document.write( "=~ 46.67 mi/hr </SPAN>\n" );
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