20. Lock Boxes. Sherman's Sherbet currently takes about 6 days to collect and deposit checks from customers. A lock-box system could reduce this time to 4 days. Collections average $15,000 daily. The interest rate is .02% per day. (LO7)

a. By how much will the lock-box system reduce float?

b. What is the daily interest savings of the system?

c. Suppose the lock-box service is offered for a fixed monthly fee instead of payment per check. What is the maximum monthly fee that Sherman's should be willing to pay for this service? (Assume a 30-day month.)