A quick-service restaurant has a single drive-through lane with one worker at the window. It is assumed that the worker can process an order every 4 minutes on average and that the processing (service) times are exponentially distributed. Customers arrive at the drive-through at the rate of 7 per hour. a. The worker at the drive-thru is busy % of time. (Enter your response rounded to two decimal places.) b. The average number of cars waiting at the drive-thru is (Enter your response rounded to two decimal places.) c. The number of cars, on average, in the drive-thru system is (Enter your response rounded to two decimal places.) d. The average time a car spends waiting in the drive-thru is minute(s). (Enter your response rounded to one decimal place.) e. The time, on average, spent in the drive-thru system is minute(s). (Enter your response rounded to one decimal place.)