For 6 months a year, the Laffer store experiences a lot of demand, so during this period it hires 40 workers. It pays each of them $100 per day. For the rest of the year, the store experiences much less demand, so it hires only 20 workers. Here too, it pays each of its workers $100 per day.
The store's demand for workers is 180 - 2L during its high sales season, and 140 - 2L the rest of the year.
Assuming all workers are identical, and that the store has no fixed expenses, how much does the store earn?