1. An entrepreneur buys an apartment building with 40 units. The previous owner charged $240 per month for a single apartment and on average rented 32 apartments at that price. The entrepreneur discovers that for every $20 he raises the price another apartment stands vacant.
A. Let x represent the number of $20 price increases. Write expressions for the new price, the number of rented apartments, and the total revenue.
B. What price should the entrepreneur charge for an apartment in order to maximize his revenue?