AU.S. Postal Service supervisor is looking for ways to reduce dress in the working department with the existing arrangement, stamped letters are machine canceled and loaded inte tubs with 425 letters per tub The tubs are then pushed to postal clerks, who read and key rip codes into an automated soiting machine at the rate of one tub per 250 seconds To overcome the stress caused when the camp canceling machine outpaces the sorting clerka pull system is proposed when the clerle are ready to process another tub of mail they will pull the tub from the canceling machine area. How many tubs should ofculate between the sorting clerks and the canceling machine if 110,000 letters are to be sted during a 6-hour shift, the safety stock policy variable, 150 25. and the average waiting time plus material handling time is 60 minutes pertub? The average processing time per tub of letters, p.ay (Enter your respon se reunded to four dearme/plona) The average waiting time per tub of letters, wis day (Enter your response rounded to four decimal places.) Theriore, the number at tubs that should circulate between the spring clarks and the canceling machine istubs (Enter your response rounded up to the next whole number)