document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1039066>Question 1039066</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Help would be appreciated for the following question:<BR>\n" );
document.write( "A coach driver has to travel 560 km. The driver A02 usually drives at an average speed of r km/h.<BR>\n" );
document.write( "He can arrive 45 minutes earlier if he increases his average speed by 6 km/h. Find the value of r correct to the nearest whole number. <BR>\n" );
document.write( "Thanks so much </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #653804 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=653804\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A coach driver has to travel 560 km. The driver A02 usually drives at an average speed of r km/h.<BR>\n" );
document.write( "He can arrive 45 minutes earlier if he increases his average speed by 6 km/h. Find the value of r correct to the nearest whole number. <BR>\n" );
document.write( ":<BR>\n" );
document.write( "r = the normal speed<BR>\n" );
document.write( "then<BR>\n" );
document.write( "(r+6) = the faster speed that gets him there 45 min earlier<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Change 45 min to .75 hrs<BR>\n" );
document.write( ":<BR>\n" );
document.write( "Write a time equation; time = dist/speed<BR>\n" );
document.write( "normal time - faster time = .75 hrs<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=560%2Fr ALIGN=MIDDLE  ALT=\"560%2Fr\"   DISABLED_style= \"max-width:90%; height:auto;\" > - <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=560%2F%28%28r%2B6%29%29 ALIGN=MIDDLE  ALT=\"560%2F%28%28r%2B6%29%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > = .75<BR>\n" );
document.write( "multiply by r(r+6), cancel the denominators and you have<BR>\n" );
document.write( "560(r+6) - 560r = .75r(r+6)<BR>\n" );
document.write( "560r + 3360 - 560r = .75r^2 + 4.5r<BR>\n" );
document.write( "form a quadratic equation on the right<BR>\n" );
document.write( "0 = .75r^2 + 4.5r - 3360<BR>\n" );
document.write( "Solve for r using the quadratic formula; a=.75; b=4.5; c=-3360<BR>\n" );
document.write( "You should get a positive solution of <BR>\n" );
document.write( "r= 64 km/hr is his normal speed<BR>\n" );
document.write( ":<BR>\n" );
document.write( ":<BR>\n" );
document.write( "confirm this solution by finding actual time at each speed<BR>\n" );
document.write( "560/64 = 8.75 hrs<BR>\n" );
document.write( "560/70 = 8.00 hrs<BR>\n" );
document.write( "-----------------<BR>\n" );
document.write( "time dif: .75 hrs which is 45 min </SPAN>\n" );
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