A company sells square carpets for ​$5 per square foot. It has a simplified manufacturing process for which all the carpets each week must be the same​ size, and the length must be a multiple of a half foot. It has found that it can sell 200 carpets in a week when the carpets are 3ft by 3​ft, the minimum size. Beyond​ this, for each additional foot of length and​ width, the number sold goes down by 4 . What size carpets should the company sell to maximize its​ revenue? What is the maximum weekly​ revenue?