[2] A nightclub charges guests a $20 cover charge to enter. Once inside, guests consume $12 worth of drinks per hour on average. Suppose A is measured in guests per hour. Express the average hourly revenue as a function of A and/or INV. A dealer of antique violins seeks exceptionally rare Stradivarius instruments and acquires those he deems authentic. He then has the instruments restored by a single expert craftsman (luthier). Once restored, the instruments are sold through auction. On average, the dealer acquires nine instruments per year, and the time between acquisitions is exponentially distributed. The luthier's time to restore an instrument is random with mean 1.2 months and standard deviation 0.3 months. The dealer's inventory holding cost is $20,000 per instrument per year, including financing and insurance costs. (a) [2] What is the mean cycle time (in months) of the restoration process (including waiting for restoration)? (b) [2] Calculate the dealer's average annual holding cost for instruments.