Powell Industries deals with customers throughout the country and is attempting to more efficiently collect its accounts receivable. A major bank has offered to develop and operate a lockbox system for Powell at a cost of $90,000 per year. Powell averages 300 receipts per day at an average of $2,500 each. Its short-term interest cost is 8% per year. Using a 360-day year, what reduction in average collection time would be needed in order to justify the lockbox system?