document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=191544>Question 191544</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A consumer electronics company sells 6.7 million MP3 players per month at a price of $100 apiece; when the price is lowered to $80, the company sells 10.2 million players per month.  How many MP3 players can the company expect to sell per month at a price of $75?\r<BR>\n" );
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document.write( "I thought I  would have to figure out cost ÷ sales. I have gotten myself so confused that I don't know which way is up. I was originally trying to figure it out in a ratio format.<BR>\n" );
document.write( "6.7 million/month    10.2 million/month               x<BR>\n" );
document.write( "$100 each                        $80	             $75<BR>\n" );
document.write( "=67,000                        =127,500<BR>\n" );
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document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #143705 by </B><A HREF=/tutors/aboutme.mpl?userid=stanbon><B>stanbon(75887)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=stanbon><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=143705\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> A consumer electronics company sells 6.7 million MP3 players per month at a price of $100 apiece; when the price is lowered to $80, the company sells 10.2 million players per month. How many MP3 players can the company expect to sell per month at a price of $75? <BR>\n" );
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document.write( "You want a function where the number of MP3 players is the dependent variable.<BR>\n" );
document.write( "You have two points: (100, 6.7 million) and (80, 10.2 million)<BR>\n" );
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document.write( "slope = (10.2-6.7) million/(80-100)<BR>\n" );
document.write( "slope = 3.5 million/ (-20) = -0.175 million<BR>\n" );
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document.write( "intercept = ??<BR>\n" );
document.write( "4.7 million = (-0.175 million)*100 + b<BR>\n" );
document.write( "4.7 million = -17.5 million + b<BR>\n" );
document.write( "b = 22.2 million<BR>\n" );
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document.write( "Equation:<BR>\n" );
document.write( "f(x) = (-0.175 million)x + 22.2 million<BR>\n" );
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document.write( "Then f(75) = -0.175 million * 75 + 22.2 million<BR>\n" );
document.write( "f(75) = 9.075 million (# of MP3s sold if the price is $75<BR>\n" );
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document.write( "Cheers,<BR>\n" );
document.write( "Stan H.<BR>\n" );
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