document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=213122>Question 213122</A>: <I><SPAN STYLE=\"word-break: break-all;\"> the average speed of a car increases from 60km/h-70 km/h, the time needed to cover a certain distance decreases by 30 minutes. what is the distance involved? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #161007 by </B><A HREF=/tutors/aboutme.mpl?userid=jonvaliente><B>jonvaliente(64)</B></A><img src=\"/images/stars/stars-08.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jonvaliente><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=jonvaliente><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=161007\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Since: Speed=Distance/Time<BR>\n" );
document.write( "And Time = Distance/Speed<BR>\n" );
document.write( "The distance did not change and we let this value be D<BR>\n" );
document.write( "When Speed = 60, Time is T, as in:<BR>\n" );
document.write( "...<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=T+=+D%2F60 ALIGN=MIDDLE  ALT=\"T+=+D%2F60\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "...<BR>\n" );
document.write( "When Speed = 70, Time is T-30 minutes(30 minutes is half an hour, speed is expressed as km/h) so, T-0.5, as in:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=T-0.5+=+D%2F70+ ALIGN=MIDDLE  ALT=\"T-0.5+=+D%2F70+\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "...<BR>\n" );
document.write( "Substituting the value of T from the first equation, we get:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28D%2F60%29-0.5+=+D%2F70 ALIGN=MIDDLE  ALT=\"%28D%2F60%29-0.5+=+D%2F70\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%28D%2F60%29-%28D%2F70%29+=+0.5 ALIGN=MIDDLE  ALT=\"%28D%2F60%29-%28D%2F70%29+=+0.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Getting the LCD, 420 we get:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%287D-6D%29%2F420=0.5 ALIGN=MIDDLE  ALT=\"%287D-6D%29%2F420=0.5\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiplying both sides by 420 we get:<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=D+=+0.5%2A420+=+210+km ALIGN=MIDDLE  ALT=\"D+=+0.5%2A420+=+210+km\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "So the distance involved is 210km<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );