Ghostbusters, Inc., exorcises (gets rid of) ghosts. During each of the next three months, the company will receive the following number of calls from people who want their ghosts exorcised: January, 100 calls; February, 300 calls; March, 200 calls. Ghostbusters is paid $800 for each ghost exorcised during the month in which the customer calls. Calls need not be responded to during the month they are made, but if a call is responded to one month after it is made, then Ghostbusters loses $100 in future goodwill, and if a call is responded to two months after it is made, Ghostbusters loses $200 in goodwill. Each employee of Ghostbusters can exorcise 8 ghosts during a month. Each employee is paid a salary of $4,000 per month. At the beginning of January, the company has 10 workers. Workers can be hired and trained (in 0 time) at a cost of $5,000 per worker. Workers can be fired at a cost of $4,000 per worker.