document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=837197>Question 837197</A>: <I><SPAN STYLE=\"word-break: break-all;\"> A charter airline finds that on its Saturday flights from Philadelphia to London, all 120 seats will be sold if the ticket price is $200. However, for each $3 increase in ticket price, the number of seats sold decreases by one.<BR>\n" );
document.write( "(a) Find a formula for the number of seats sold if the ticket price is P dollars.<BR>\n" );
document.write( "(b) Over a certain period, the number of seats sold for this flight ranged between 90 and 115. What was the corresponding range of ticket prices?\r<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 #504519 by </B><A HREF=/tutors/aboutme.mpl?userid=Theo><B>Theo(13342)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=Theo><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=Theo><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=504519\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> there are 2 formulas that can be used.\r<BR>\n" );
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document.write( "the first formula solves for the price per ticket based on the number of tickets sold.<BR>\n" );
document.write( "that formula is:<BR>\n" );
document.write( "P = 200 + 3 * (120 - T))<BR>\n" );
document.write( "if you sell 120 tickets, the price per ticket is 200.<BR>\n" );
document.write( "if you sell 119 tickets, the price per ticket is 200 + (3*1) = 200 + 3 = 203.<BR>\n" );
document.write( "if you sell 118 tickets, the price per ticket is 200 + (3*2) = 200 + 6 = 206.<BR>\n" );
document.write( "if you sell 121 tickets, the price per ticket is 200 + (3*(-1)) = 200 - 3 = 197.<BR>\n" );
document.write( "if you sell 122 tickets, the price per ticket is 200 + (3*(-2)) = 200 - 6 = 194.\r<BR>\n" );
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document.write( "the second formula solves for the number of tickets sold based on the price per ticket.<BR>\n" );
document.write( "that formula is:<BR>\n" );
document.write( "T = 120 - ((P - 200) / 3))<BR>\n" );
document.write( "if the price per ticket is 200, the number of tickets sold is 120.<BR>\n" );
document.write( "if the price per ticket is 203, the number of tickets sold is 120 - (3/3) = 120 - 1 = 119.<BR>\n" );
document.write( "if the price per ticket is 206, the number of tickets sold is 120 - (6/3) = 120 - 2 = 118.<BR>\n" );
document.write( "if the price per ticket is 197, the number of tickets sold is 120 - (-3/3) = 120 + 1 = 121.<BR>\n" );
document.write( "if the price per ticket is 194, the number of tickets sold is 120 - (-6/3) = 120 + 2 = 122.\r<BR>\n" );
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document.write( "depending on your needs, you can use one formula or the other.\r<BR>\n" );
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document.write( "for example, question b asks:\r<BR>\n" );
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document.write( "Over a certain period, the number of seats sold for this flight ranged between 90 and 115. What was the corresponding range of ticket prices? \r<BR>\n" );
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document.write( "you would want to use the formula that gives you the price per ticket for the number of tickets sold.<BR>\n" );
document.write( "that formula is:<BR>\n" );
document.write( "P = 200 + 3 * (120 - T))\r<BR>\n" );
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document.write( "when T = 90, that formula tells you that the price per ticket is equal to:<BR>\n" );
document.write( "200 + 3 * (120 - 90) which is equal to 200 + 3 * (30) which is equal to 200 + 90 which is equal to 290.\r<BR>\n" );
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document.write( "when T = 115, that formula tells you that the price per ticket is equal to:<BR>\n" );
document.write( "200 + 3 * (120 - 115) which is equal to 200 + 3 * (5) which is equal to 200 + 15 which is equal to 215.\r<BR>\n" );
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