the questlaser eye surgeryser Eye Clinic (LEC) is the only provider of laser eye surgery in a medium-sized city. Its fixed costs are $2.5 million per year. Its variable (and marginal) cost of each surgery is $500. Demand for its surgeries can be written as P = 2,500 – 0.25Q, which means that MR = 2,500 – 0.50Q, where P is the price of the surgery, MR is marginal revenue, and Q is the number of surgeries performed each year.

How many surgeries will LEC perform each year to maximize profits?

I know the answer should be 4000.
But have no idea how to reach that.