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A firm has daily cash receipts of $300,000 and is interested in acquiring a lockbox service in order to reduce collection time. Bank 1’s lockbox service costs $3,000 per month and will reduce collection time by 3 days. Bank 2’s lockbox service costs $5,000 per month and will reduce collection time by 4 days. Bank 3’s lockbox service costs $500 per month and will reduce collection time by 1 day. Bank 4’s lockbox service costs $1,000 per month and will reduce collection time by 2 days. If money market rates are expected to average 6% during the year, and the firm wishes to maximize income, which bank should the firm choose?