document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=201710>Question 201710</A>: <I><SPAN STYLE=\"word-break: break-all;\"> If a race car can go around a track in 5 minutes,then how long will it take to go around the track if it increases its speed by 20%?  </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #151972 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=151972\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> the answer should be 5/1.2 = 4.16666666 minutes = 4 minutes and 10 seconds.<BR>\n" );
document.write( "here's how I got it.<BR>\n" );
document.write( "basic formula is rate * time = distance.<BR>\n" );
document.write( "D is going to be the same so we call it D.<BR>\n" );
document.write( "The rate will be different so we'll call it R1 and R2.<BR>\n" );
document.write( "the time will be different so we'll call it T1 and T2.<BR>\n" );
document.write( "we know the following:<BR>\n" );
document.write( "R1 * T1 = D<BR>\n" );
document.write( "T1 = 5, so<BR>\n" );
document.write( "R1 * 5 = D<BR>\n" );
document.write( "we know that R2 will be 20% more than R1 so we know that R2 = 1.2 * R1.<BR>\n" );
document.write( "we can make a general equation for R2 that says<BR>\n" );
document.write( "R2 * T2 = D<BR>\n" );
document.write( "R2 will be different.<BR>\n" );
document.write( "T2 will be different.<BR>\n" );
document.write( "D will remain the same.<BR>\n" );
document.write( "since we know that R2 = 1.2 * R1, we can substitute to get<BR>\n" );
document.write( "1.2 * R1 * T2 = D<BR>\n" );
document.write( "since they both = D, we can make them equal to each other, so we have<BR>\n" );
document.write( "R1 * T1 = 1.2 * R1 * T2<BR>\n" );
document.write( "since we know that T1 = 5, we can substitute in the equation to get<BR>\n" );
document.write( "R1 * 5 = 1.2 * R1 * T2<BR>\n" );
document.write( "if we divide both sides of the equation by 1.2 * R1, then we get<BR>\n" );
document.write( "5/1.2 = T2<BR>\n" );
document.write( "simplifying gets 4.16666666 = T2<BR>\n" );
document.write( "taking the fraction and converting it to minutes we get<BR>\n" );
document.write( ".1666666666 * 60 = 10<BR>\n" );
document.write( "which gets us<BR>\n" );
document.write( "4 minutes and 10 seconds.<BR>\n" );
document.write( "to check this out, we make an assumption by saying the distance is an arbitrary number such as 10 miles.<BR>\n" );
document.write( "In order for this to be done in 5 minutes, the car has to go 10 / 5 minutes = 2 miles a minute which equates to 120 miles an hour.<BR>\n" );
document.write( "if we raise 2 miles a minute by 20% we get 2.4 miles a minute which equates to 144 miles an hour.<BR>\n" );
document.write( "at 2.4 miles a minute, it takes 10 / 2.4 minutes to complete the distance which equals 4.166666666 minutes which gets us to our answer so we're good.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );