Schrute Farm Sales buys portable generators for $460 and sells them for $750. He pays a sales commission of 5% of sales revenue to his sales staff. Mr. Schrute pays $7000 a month rent for his store, and also pays $1800 a month to his staff in addition to the commissions. Mr. Schrute sold 300 generators in June. If Mr. Schrute prepares a contribution margin income statement for the month of June, what would be his contribution margin?