document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1155672>Question 1155672</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Yesterday, John bought 5 deluxe hamburgers and 2 orders of cheese fries from the Hamburger Palace and paid $23.65. Today John purchased 3 deluxe hamburgers and 1 order of cheese fries and paid $13.80. What is the price of one deluxe hamburger? What is the price of one order of cheese fries? </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #778300 by </B><A HREF=/tutors/aboutme.mpl?userid=greenestamps><B>greenestamps(13200)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=greenestamps><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=greenestamps><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=778300\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> <br><BR>\n" );
document.write( "Suppose that today, instead of 3 burgers and 1 fries for $13.80, he had bought twice as much -- 6 burgers and 2 fries for $27.60.<br><BR>\n" );
document.write( "Then the difference between yesterday's purchase and today's would be 1 more burger for $3.95.<br><BR>\n" );
document.write( "So the price of a burger is $3.95; from there it is easy to find the price of an order of fries.<br><BR>\n" );
document.write( "That informal solution using logical reasoning follows exactly the same path as a formal algebraic solution using elimination:<br><BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=5h%2B2f+=+23.65 ALIGN=MIDDLE  ALT=\"5h%2B2f+=+23.65\"   DISABLED_style= \"max-width:90%; height:auto;\" >  -- (1) yesterday<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=3h%2Bf+=+13.60 ALIGN=MIDDLE  ALT=\"3h%2Bf+=+13.60\"   DISABLED_style= \"max-width:90%; height:auto;\" >  --  (2) today<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=6h%2B2f+=+27.60 ALIGN=MIDDLE  ALT=\"6h%2B2f+=+27.60\"   DISABLED_style= \"max-width:90%; height:auto;\" >  --  (3) today's, doubled<BR>\n" );
document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=h+=+3.95 ALIGN=MIDDLE  ALT=\"h+=+3.95\"   DISABLED_style= \"max-width:90%; height:auto;\" >  --  the difference between (1) and (3)<br><BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );