You have just opened a new nightclub Russ Techno Pitstop but
     You have just opened a new nightclub, Russ\' Techno Pitstop, but are unsure of how high to set the cover charge (entrance fee). One week you charged $10 per guest and averaged 300 guests per night. The next eek you charged $12 per guest and averaged 260 guests per night.  (a) Find a linear demand equation showing the number of guests q per night as a function of the cover charge p.  q(p) =  (b) Find the nightly revenue R as a function of the cover charge p.  R(P) =  (c) The club will provide two free non-alcoholic drinks for each guest, costing the club $3 per head. In addition, the nightly overheads (rent, salaries, dancers, D, etc.) amount to $1,000. Find the cost C as a function of the cover charge p.  C(p) =  (d) Now find the profit in terms of the cover charge p.  P(p) =  Determine the entrance fee you should charge for a maximum profit.  p = $  per guest
 
  
  Solution
(p1,q1)=(10,300),(p2,q2)=(12,260)
(a)
linear demand equation
q-300=[(260-300)/(12-10)](p-10)
=>q-300=-20(p-10)
=>q-300=-20p+200
=>q=500 -20p
linear demand equation is q(p)=500 -20p
-----------------------------------------------------------
(b) revenue R=p*q
revenue R(p)=p*(500 -20p)
revenue R(p)=(500p -20p2)
--------------------------------------------------------------
(c)
cost C=1000 +3q
cost C(p)=1000 +3(500 -20p)
cost C(p)=2500 -60p
--------------------------------------------
(d)
profit P(p)=R(p)-C(p)
profit P(p)=(500p -20p2)-(2500 -60p)
profit P(p)=(-2500+560p -20p2)
P(p)=-2500- (20(-28p +p2))
P(p)=-2500- (20(-196+196-28p +p2))
P(p)=-2500+3920- (20(196-28p +p2))
P(p)=1420- (20(p-14)2)
vertex is (14,1420)
entrance fee for a maximum profit is p=$14 per guest


