document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=376163>Question 376163</A>: <I><SPAN STYLE=\"word-break: break-all;\"> on a recent trip, a trucker traveled 330 mi at a constant rate.  because of road construction, the trucker then had to reduce the speed by 25 mph.  an additional 30 mi was traveled at the reduced rate.  the total time for the entire trip was 7 h.  find the rate of the trucker for the first 330 mi. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #267582 by </B><A HREF=/tutors/aboutme.mpl?userid=mananth><B>mananth(16946)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=mananth><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=mananth><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=267582\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> let speed for 330 miles be x<BR>\n" );
document.write( "next 30 miles x-25 mph.<BR>\n" );
document.write( "...<BR>\n" );
document.write( "time for 330 miles +time for 30 miles = 7<BR>\n" );
document.write( "..<BR>\n" );
document.write( "t=d/r<BR>\n" );
document.write( "330/x + 30/(x-25)=7<BR>\n" );
document.write( "LCD = x(x-25)<BR>\n" );
document.write( "(330(x-25)+30x )/(x(x-25)= 7<BR>\n" );
document.write( "..<BR>\n" );
document.write( "(330x-8250+30x)/(x(x-25)=7<BR>\n" );
document.write( "...<BR>\n" );
document.write( "360x-8250 = 7*(x(x-25)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "360x-8250 = 7x^2-175x<BR>\n" );
document.write( "7x^2-360x-175x+8250=0<BR>\n" );
document.write( "7x^2-535x+8250=0<BR>\n" );
document.write( "...<BR>\n" );
document.write( "find roots x1,x2 by quadratic formula<BR>\n" );
document.write( "discriminant =b^2-4ac= 55225<BR>\n" );
document.write( "...<BR>\n" );
document.write( "x1=(535+sqrt(55225))/14<BR>\n" );
document.write( "x1=55 mph<BR>\n" );
document.write( "..<BR>\n" );
document.write( "x2= (535-sqrt(55225))/14<BR>\n" );
document.write( "x2=21.42 mph. ( not possible since speed was reduced by 25 mph.)<BR>\n" );
document.write( "..<BR>\n" );
document.write( "So speed = 55 mph for the 330 mile part<BR>\n" );
document.write( "...<BR>\n" );
document.write( "m.ananth@hotmail.ca<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );