document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=458643>Question 458643</A>: <I><SPAN STYLE=\"word-break: break-all;\">  Suppose you have a cookie stand, and when you charge $3 per cookie<BR>\n" );
document.write( "box you sell 200 boxes. But when you raise your price to $4 you only<BR>\n" );
document.write( "sell 120 boxes. \r<BR>\n" );
document.write( "\n" );
document.write( "a.   Write an equation for the number of boxes you sell as a function of<BR>\n" );
document.write( "the price you charge. \r<BR>\n" );
document.write( "\n" );
document.write( "b.   Denote \"B\" for number of boxes, and \"P\" for the price you charge.\r<BR>\n" );
document.write( "\n" );
document.write( "c.   Assume the function is linear..     </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #314700 by </B><A HREF=/tutors/aboutme.mpl?userid=lwsshak3><B>lwsshak3(11628)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=lwsshak3><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/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=314700\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> Suppose you have a cookie stand, and when you charge $3 per cookie<BR>\n" );
document.write( "box you sell 200 boxes. But when you raise your price to $4 you only<BR>\n" );
document.write( "sell 120 boxes. <BR>\n" );
document.write( "a. Write an equation for the number of boxes you sell as a function of<BR>\n" );
document.write( "the price you charge. <BR>\n" );
document.write( "b. Denote \"B\" for number of boxes, and \"P\" for the price you charge. <BR>\n" );
document.write( "c. Assume the function is linear.<BR>\n" );
document.write( "..<BR>\n" );
document.write( "Since function is linear, we will be using the standard form: y=mx+b, with m=slope, b=y-intercept<BR>\n" );
document.write( "For given problem:<BR>\n" );
document.write( "B=mP+b<BR>\n" );
document.write( "Given are two points on the (P,B) curve,(3,200) and (4,120)<BR>\n" );
document.write( "slope, m=&#8710;B/&#8710;P=(200-120)/(3-4)=80/-1=-80<BR>\n" );
document.write( "B=-80P+b<BR>\n" );
document.write( "plug in B & P from one of given points to solve for b, the y-intercept<BR>\n" );
document.write( "200=-80*3+b<BR>\n" );
document.write( "b=200+240=440<BR>\n" );
document.write( "Equation: B=-80P+440 </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );