A grocery store has three open checkout lanes. On average, 45 shoppers arrive at these lanes per hour. The coefficient of variation of the interarrival time is equal to one. The average service time for all the lanes is 18 customers per hour, and the coefficient of variation of the service time distribution for all three lanes is three minutes. What is the percentage decrease in utilization when one more checkout lane is added to the system?

Costco wholesale corporation operates membership warehouses selling food, appliances, consumer electronics, apparel and other household goods at 471 locations across the u.s. as well as in canada, mexico and puerto rico. as of its fiscal year-end 2005, costco had approximately 21.2 million members. selected fiscal-year information from the company's balance sheets follows. ($ millions). selected balance sheet data 2005 2004 merchandise inventories $4,015 $3,644 deferred membership income (liability) 501 454 (a) during fiscal 2005, costco collected $1,120 cash for membership fees. use the financial statement effectstemplate to record the cash collected for membership fees. (b) in 2005, costco recorded $46,347 million in merchandise costs (that is, cost of goods sold). record thistransaction in the financial statement effects template. (c) determine the value of merchandise that costco purchased during fiscal-year 2005. use the financial statementeffects template to record these merchandise purchases. assume all of costco's purchases are on credit.