Inman Recycling, Inc., collects and compacts aluminum cans and glass bottles in Reston, Louisiana. Its truck drivers currently wait an average of 15 minutes before emptying their loads for recycling. The cost of driver and truck time while they are in queues is valued at $60 per hour. A new automated compactor can be purchased to process truckloads at a constant rate of 12 trucks per hour (that is, 5 minutes per truck). Trucks arrive according to a Poisson distribution at an average rate of 8 per hour. If the new compactor is put in use, the cost will be amortized at a rate of $3 per truck unloaded.

APPROACH c CEO Tony Inman hires a summer college intern to conduct an analysis to evaluate the costs versus benefits of the purchase. The intern uses the equation for Wq in Table D.6