In the event he requires an appendectomy, David's demand for hospital accommodations is as shown in the diagram. David's current insurance policy...

1. In the event he requires an appendectomy, David's demand for hospital accommodations is as shown in the diagram. David's current insurance policy fully covers the cost of hospital stays. The marginal cost of providing a hospital room is $150 per day. If David's only illness this year results in an appendectomy, how many days will he choose to stay in the hospital?