document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=679082>Question 679082</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A rental car costs a minimum charge plus a fixed charge per mile driven. One customer was charged $60 for 160 miles of use. Another customer drove 280 miles and paid $90. Write an equation relating the total cost, C (in dollars), to the miles driven, x. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #421792 by </B><A HREF=/tutors/aboutme.mpl?userid=partha_ban><B>partha_ban(41)</B></A><img src=\"/images/stars/stars-07.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=partha_ban><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=partha_ban><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=421792\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Assume m = minimum charge<BR>\n" );
document.write( "and r = fixed charge per mile<BR>\n" );
document.write( "Therefore, C = m + r.x ... ... ...(A)<BR>\n" );
document.write( "where C = Total cost <BR>\n" );
document.write( "and x = miles driven<BR>\n" );
document.write( "So, 60 = m + 160r ... ... ...(1)<BR>\n" );
document.write( "and, 90 = m + 280r ... ... ...(2)<BR>\n" );
document.write( "Subtracting (1) from (2),<BR>\n" );
document.write( "120r = 30<BR>\n" );
document.write( "r = 30/120 = 1/4<BR>\n" );
document.write( "Substituting r = 1/4 in (1),<BR>\n" );
document.write( "m + 160*1/4 = 60<BR>\n" );
document.write( "m + 40 = 60<BR>\n" );
document.write( "m = 60 - 40<BR>\n" );
document.write( "m = 20<BR>\n" );
document.write( "Therefore from (A):<BR>\n" );
document.write( "C = 20 + x*1/4<BR>\n" );
document.write( "C = 20 + x/4 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );