Bostons Dairy has just opened its main yogurt factory in upstate Massachusetts. This main factory can produce 3,500 boxes of yogurt monthly (each box contains twelve 6-oz cups). Due to overwhelming demand for the companys product, Bostons Dairy has signed a contract to rent a new factory, which can produce up to 8,000 boxes per month. The monthly total fixed costs are $40,000 in the main factory and $16,000 in the new factory. The variable production cost of yogurt is $4.50 per box in the main factory. The variable production cost in the new factory is $6.0 per box as materials have to be redistributed from the main factory. The average selling price is $15, and the variable selling expense is $1 per box, which is the same for all factories. In addition, Bostons Dairy plans to pay its sales force $0.80 per box as added bonus for every box sold above the break-even point. How many boxes does the company have to produce and sell in order to earn a net operating income of $10,000 per month (round all decimal up to one box)