Suppose you own an apartment building containing 100 units. If you charge $400 per
month for each unit, then all units can be rented out. For every $20 increase in monthly rent, you
will lose one customer. What monthly rent should you charge to maximize your revenue? Show that
the corresponding revenue is an absolute maximum.
completing the square method:
both yield 400 as answer which would make max rent 8400 which is incorrect. IS my formula wrong? Where did i go wrong