document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=1194365>Question 1194365</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A caterer charges $120 to cater a party for 15 people <BR>\n" );
document.write( "and $200 for 25 people. Assume that the cost, y, is a <BR>\n" );
document.write( "linear function of the number of x people. Write an <BR>\n" );
document.write( "equation in slope-intercept form for this function. <BR>\n" );
document.write( "What does the slope represent? How much would a <BR>\n" );
document.write( "party for 40 people cost? <BR>\n" );
document.write( "y = 15x + 120<BR>\n" );
document.write( "y = 8x + 120<BR>\n" );
document.write( "y = 8x<BR>\n" );
document.write( "y = 10x + 80 </SPAN>\n" );
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document.write( "The cost goes up by $200-$120 = $80 when the number of people goes up by 25-15 = 10; the slope is 80/10 = 8.  So the equation is of the form<br><BR>\n" );
document.write( "y = 8x+b<br><BR>\n" );
document.write( "Use either given data point to find b:<br><BR>\n" );
document.write( "120 = 8(15)+b<BR>\n" );
document.write( "120 = 120+b<BR>\n" );
document.write( "b = 0<br><BR>\n" );
document.write( "ANSWER: y = 8x<br><BR>\n" );
document.write( "The slope of 8 means the cost goes up by $8 for each additional person.<br><BR>\n" );
document.write( "The cost for a party for 40 people is 40($8) = $320.<br><BR>\n" );
document.write( " </SPAN>\n" );
document.write( "</TD></TR></TABLE>\n" );