document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1020249>Question 1020249</A>: <I><SPAN STYLE=\"word-break: break-all;\"> The cost of petrol increased by 15% one week but fell back to the original price the next week. <BR>\n" );
document.write( "By what percentage did the cost of petrol fall in the second week? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #636158 by </B><A HREF=/tutors/aboutme.mpl?userid=Fombitz><B>Fombitz(32388)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Fombitz><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=Fombitz><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=636158\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Let's say the price starts at X.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P=X ALIGN=MIDDLE  ALT=\"P=X\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "During the 15% increase,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P=%281%2B15%2F100%29X=1.15X ALIGN=MIDDLE  ALT=\"P=%281%2B15%2F100%29X=1.15X\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "During the unknown decrease,<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P=%281%2BY%2F100%29%281.15X%29 ALIGN=MIDDLE  ALT=\"P=%281%2BY%2F100%29%281.15X%29\"   DISABLED_style= \"max-width:90%; height:auto;\" > \"Y is the percentage decrease you're looking for\"<BR>\n" );
document.write( "Make that new price equal to the original price, X.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%281%2BY%2F100%29%281.15%29X=X ALIGN=MIDDLE  ALT=\"%281%2BY%2F100%29%281.15%29X=X\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "You can divide X out of both sides.<BR>\n" );
document.write( "Now solve for Y.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=1.15%2B%281.15Y%29%2F100=1 ALIGN=MIDDLE  ALT=\"1.15%2B%281.15Y%29%2F100=1\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Subtract 1.15 from both sides<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=%281.15%29Y%2F100=-0.15 ALIGN=MIDDLE  ALT=\"%281.15%29Y%2F100=-0.15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "Multiply both sides by 100 and divide both sides by 1.15.<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Y=-15%2F1.15 ALIGN=MIDDLE  ALT=\"Y=-15%2F1.15\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=Y=-13.04 ALIGN=MIDDLE  ALT=\"Y=-13.04\"   DISABLED_style= \"max-width:90%; height:auto;\" ><BR>\n" );
document.write( "About a 13% decrease.<BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );